Started researching general 3D level design, heres a few links.

http://en.wikipedia.org/wiki/Level_design

http://gamasutra.com/features/20060425/shahrani_01.shtml

http://gamasutra.com/features/20060428/shahrani_01.shtml

http://www.cliffyb.com/rants/art-sci-ld.shtml