I had a spare HDD but it was not on the compatibility list. After a lot of toying around, I managed to figure out a way to still get it to work. Here's my proof-of-concept demo video: Don't attempt unless you don't care much about your ps2 or your hdd. http://www.youtube.com/watch?v=H2doRzow5D0 Let me know what you think!
Hmm, nice I guess. I don't have a network adapter, but you could use a 2.5" Laptop hard drive I guess, by buying a 3.5" to 2.5" adapter on eBay.
that method is already known. ps2drives.x-pec.com has that method for the western digital drives. you can see it HERE
Cool, didn't know about that site. You may want to buy a 2.5" external usb enclosure instead. That way you can use it as a ps2 and PC external drive.