Here Is My Guide On Upgrading Your Mac Mini......This is only a short guide for now but will be expanded over time....

RAM - RAM is the most commonly upgraded component of a computer. More ram adds to your system speed and primarily allows you to have more applications open at one time.

The Mac Mini Ram MUST meet the following specifications:

MAXIMUM 1GB (1024mb)
PC2700 or PC3200
333Mhz or 400Mhz
184 Pin
DDR RAM (NOT DDR2 or SODIMM )

your mac mini only has one RAM bay so you can only have one memory module installed at a time, this means a maximum or 1GB of RAM.




Hard-Drive (HDD)

this is probably one of the most difficult parts of the computer to upgrade.
The HDD hold all of you programs and you documents / music / pictures ect.

the mac mini has capacity for ONE 2.5" IDE hard drive (the same types as in laptops)
To be honest you will be much better off buying an external hard drive than trying to upgrade the hdd in a mac mini.
2.5" drives are very expensive and the biggest one in production is only 100gb.

however if you do want to upgrade you hard drive this is how you do it.

1) take out your old hdd
2) get (off ebay somewhere) a 2.5" to 3.5" hard drive adapter.
3) plug the mac minis hard drive into another computer as a slave drive
4) copy EVERYTHING off the macs hdd into a safe place on the computer disk.
5) swap over the old 2.5" drive for the new one
6) format it
7) put EVERYTHING off the macs drive onto the new one
8)plug it back in and fire it up

WARNING !!!
------do not format the old mac mini hard drive until you have the new one working perfectly
------when plugging in / unpluggin a hard drive, the computer MUST be OFF, hard drives are not hot swapable