There's been a few revisions to the R500 3D documentation since the original February 2008 release and the most recent one has just come over the night.
Version 1.5 of the R500 3D programming documentation is this newest revision and it provides expanded coverage of AA resolve and fast clears. This newest document, which is titled R5xx_Acceleration_v1.5.pdf, now puts the page count up to 288 pages. Of course, there is already good OpenGL/3D acceleration support within the classic Mesa driver stack and what's becoming superb in terms of both features and performance within the Radeon Gallium3D driver up through the R500 series, but this expanded documentation may prove to still be of use in some areas or for those new graphics driver developers wishing to learn about the ATI R500 GPU acceleration architecture.
The newly-revised document can be found at X.Org.