we have not removed documentation, if stuff was removed by the authors, the online documentation is as it was,
It looks to me as if you can still buy the docs. The link might have been broken for a little while.
What happened to the online docs is that someone tagged versions for 2.4 and 3.0, so I removed the 2.4 only stuff from the 3.0 branch. However, no one got around to putting the 2.4 version onto the website (I'm not sure how to do it). You can look in cvs for the branch_2_4 tag.