from the perspective of someone who has modded several xboxes successfully, I find the ps2 much more difficult, like you said it is alot smaller, but stick around this site and they will never steer you wrong, once you get the hang of it, it's all good!
With good soldering skills i figure you could pull it off.
Here is what you are looking at (as done by a professional)
http://www.teammodders.com/forum/viewfor...9d9a3a8e8260b52 there are install pictures for all different chips and models, in another section of the forums they also have install diagrams and instructions.
if youve done xbox well, then ps2 shouldnt be too hard. i went from first time solder of ps1 directly to ps2. i ended up making it work.
@steimy
dude, those pics are so nice. haha i tried to make mine like that the 2-3rd time i installed a mod chip and it came out better, but not like that.
If you just plan on doing one chip, I'd say it's more cost effective to have a pro do it. I started off modding my brother's PS2, and I spent more on all the tools/wire/etc that it would have cost to get it done by someone else.
However, I enjoy modding PS2's moreso than Xbox's. You definitely feel accomplished after all that work.