In my quest to know more about the PS2's video, and hopefully trick the PS2 into Progressive Scan without a boot disc like Xploder HDTV, I did some googling and found this page:
It is here that you can download a copy (in PDF) of a Service Manual (complete with a secondary manual) for SCPH-30000 model PS2's. Contains detailed schematic and circuit board information along with parts lists. The secondary manual shows you how to disassemble a Version 4 PS2.
Very, very useful for those wanting to know more about their older PS2's (and hack them up).
According to this page it is a very recent upload (last month). Although it says that this is in multi-part form you only need to download the file on that page. The other files appear to be empty folders.
(By the way, what's this rule about not being allowed to post links to other URLs until after 15 posts about?)