Lukasz Bruun, a long time contributor to the ps2dev scene has put together a great introduction to PS2 homebrew development. It covers all you need to know about the ps2dev tools, hardware & software. It also has a great history of the ps2dev community with many of the important releases since 2001. Check it out over at Lukasz' site.
http://lukasz.dk/playstation-2-programming/an-introduction-to-ps2dev/. If you've got any comments you can give him feedback in the forums
here.