I thought I'd write a guide for people who are looking to buy a small, handheld PDA (personal device assistant) just to read books and nothing else. First, I will outline the difference between the two formats of PDA: the Palm and the Pocket PC. I will talk about the various factors you'll need to consider when buying a PDA on Ebay. The actual process of putting an Ebook onto your Palm is quite simple and I will discuss this at the end of the guide. There are thousands of great books you can download for free from Project Gutenberg, which is an enormous resource and there are other websites where you can pay for generally newer, Tom Clancy type titles.

As an overview, the PDA market bloomed for about ten years until 2005 and was fiercely fought between Palm and the Pocket PC brigade. That battle is finished, really, because the market has evolved into segments, such as smart phones, dedicated multimedia devices, sat-nav, games machines and web-browsers. If you go into Argos or Dixons, you probably won't find a single PDA now.

The main differences between machines made by Palm (or those which licensed its operating system, such as Sony and Handspring) and the Pocket PC, is that Palms are small, relatively cheap and pretty basic, whilst Pocket PC's (Acer, Toshiba, Ipaq and Dell Axims) are based on Microsoft and offer lots of software that you'll never use. Generally, Palms have stronger battery life, but that depends how you use your machine and, for PDA's with colour screens, the brightness setting you select. An old monochrome Palm Vx or M500 can be kept on for a whole day on a single charge (probably longer). But you probably couldn't make an Ipaq 1930 on max brightness last a train journey out of London. I will discount the Pocket PC from my guide, not because I don't like them, but because, fundamentally, you just don't need that much hardware resource to read a book.

So let's look at the Palm. Palm and its allies made many models: the Palm III, the M100 series, the Vx/500 series, the Tungstens, the Zires. There was also the Handspring Visor (highly rated) and all the Sony Clie models, which were excellent. I won't run through all of them, but the machines I really like for Ebook reading are these: the Palm Vx (or IBM C3 clone), the Palm M500, the Sony Clie TJ25 and the Tungsten E2.

The Palm Vx is a lovely old machine. 8mb of memory (even Lord of the Rings is only 1mb in the Palm format), great battery life, robust and reliable. It doesn't take a memory card and is pre-USB (connection is through a serial cable) but that doesn't matter. But, as a monochrome screen with a very primitive backlight, it's not really ideal for a place or an environment with poor light.

The Palm M500 is just like the Palm Vx, but it has a slightly faster processor and takes a memory card, which means you don't have any 'hotsync' issues to worry about between the PDA and computer. I love it.

The Clie TJ25 is a really nice machine with a lovely high-resolution colour screen. This Clie has a little scroll button on its side, which is great for zipping quickly through pages with your thumb. If you buy this machine, make sure you get the desktop connection software, because Sony gadgets will only use their proprietary memory cards, rather than standard MMC/SD cards.

The Tungsten E2 was probably the last decent PDA Palm made. Great colour screen, takes a memory card, really strong battery life. There can be a problem with a buzzing sound from the screen (I won't bore you with the technical details), but this can be muted through a simple and quick operation: unscrew the back and place a thin strip of card around  the border between the digitizer sheet and the actual screen. Performance is unaffected. I've muted loads of Palms this way and it's perfectly safe. Lots of people I know have a Tungsten E2.

Now let's examine the various factors that will influence your decision: price, battery, weight and screen.

Price: How much do you want to spend? For about £15, you can get an old black and white Palm Vx or an M500. For £25, the Sony Clie TJ 25 and for £45, the Tungsten E2. For the M500 and the Tungsten E2, I'd advise a memory card and a USB card-reader, but these are peanuts on Ebay now. In fact, a bag of peanuts is probably more expensive.

Battery: Don't get too anxious about battery life, but keep a regular charge, either through the mains adaptor or a USB cable to your PC. All the models I've nominated above have strong internal rechargable batteries, which means you can take the PDA on a long journey and not worry about losing power just before the crucial moment on the final page when you find out who poisoned the businessman with arsenic in his tea. Reading an Ebook doesn't hurt the processor too much, anyway. If you've bought a used machine on Ebay, make sure you ask the seller about battery life. If you are unhappy with the reply, move away and wait. You can buy a replacement PDA battery, but that will cost you about seven pounds and may require special tools to open the PDA.

Weight: I'm acutely aware of weight in my hand, because I have osteopororis (weak bones) as a result of colitis. When I test a PDA, I want to know whether I will be able to hold it in my hand for 30 or 40 minutes without an ache. 140g is the maximum, which is about the weight of a paperback. The models above are pretty lightweight, although I'd say that the Clie is slightly heavier than the others. But you can put any of them in your trouser pocket and not worry about the weight.

Screen: This is the most important factor of all and will dictate your purchasing decision, because I don't know where you are generally going to read your Ebook. As a starting point, putting a large, bold font on a screen is all you need to read text. In normal conditions, black and white is just as good as high-resolution and may even be easier on the eye, as there are fewer colour shades and pixels to absorb. For some reason, my brain feels more fatigued staring at a high-res screen. Certainly, in sunshine in a park or a cafe,  the Palm Vx or Palm M500 are far, far easier to read than gazing at the polar glare of a Tungsten E2 or a Clie TJ25. If that sounds like I'm pushing you towards these models, then be aware than, conversely, in poor lighting conditions, whilst the colour screens of the E2 and TJ25 are delightful, especially when applied with soft pastel shades, the Vx and M500 struggle. They do have primitive backlights, but a 1970's style phosphoric green font does not really make a pleasant reading environment.

Have you made your decision yet? If it helps, read some reviews of these PDA's on Epinions, Amazon or Gadgeteer. But don't get stuck in the paralysis of analysis. If I absolutely had to make one choice, it would probably be the Palm M500. Or why not buy two? A cheap travelling companion Vx or M500 and a colour Tungsten E2 or Clie TJ25 for indoor and evening use. You can quickly infra-red beam ebooks between Palms or switch between them with the memory card.

Right, you have bought your Palm PDA and you are familiar with its functionality, particularly how to install files through 'hotsync' connection or memory card. This is very easy and requires little technical skill. Since you won't use the PDA for any other function than Ebook reading, you don't need to worry about address books, password protection or multimedia.

Now it's time to read a book on it. Well, the first action is to install Ebook software. I use Plucker. Download Plucker onto your PC and then install it on your PDA. I wouldn't take the latest release of Plucker, because it may be unstable on an old PDA and you don't need the really advanced features for web-browsing, so an older version is fine.

Essentially, you'll download a book onto your computer from, say, Gutenberg, in .txt format (or unzip it) and convert it into the Palm Plucker format. Plucker is great, because it's free, simple to use and its files actually use less memory than .txt files. On your PDA, you can categorise ebooks in your library, change fonts, search through text for a certain word and make bookmarks. You can assign buttons to scroll up and down the pages.

Once the downloaded ebook has been converted into Plucker file format, you can put it on your PDA, either through the hotsync connection process or via a memory card. And now you have an ebook reader!

I hope this helps you.

Regards