www.opengl.org has the functions on there site, but is there a downloadable version?

I find the SDK very crappy...
Try to look on google for "The Official Guide to Learning OpenGL"
It''s a VERY good book, with lots of examples, and it''s free for download.

Height Map Editor | Eternal lands

http://www.opengl.org/developers/documentation/specs.html has pdfs

Check the very bottom of this site. There''s a link to a zip containing the entire OpenGL red book, a very useful book indeed.

http://fly.cc.fer.hr/~unreal/theredbook/