Koroush over at TweakGuides has finished his, well, tweak guide for BF2. Anything & everything you ever wanted to know about config'ing the crap outta that game is over there. The last section on the .con files is worth a look.

"Following on from my initial release of the BF2 Demo Tweak Guide, this full version guide contains nine pages of information designed to explain BF2's settings, provide an insight into the reasons behind many common problems, and provide some handy tips and tweaks for you to try."