bottle necking e6600 with 2 8800gtx in sli?

I've heard that the 8800gtx can be bottlenecked by the cpu. I currently run an e6600 @ 2.4 ghz with a single 8800gtx, and it seems to work fine. Question is, do you think adding a second 8800gtx would cause a bottle neck at my cpu?

I actually have a 24 inch dell monitor on order, so ill be playing at the 1920 x 1200 reso, the reason for thinking of adding a second vid card.

I have read alot of posts saying how easy it is to overclock the 6600 to 3.0/3.2 ghz, it's just that ive never done an overclock before and im kinda scared of it lol. Would I see a big performance boost in fps in a game like crysis with the cpu overclock?

Guess I really need to just step up and tune my system. Currently I run the 6600 @ 2.4 ghz, 4gb corsair 8500c5 dominator ram @ 1066, 680i mobo, with vista 64. From the article's and posts ive read, the proper tune would be cpu @ 3.2 ghz, and ram @ 800 mhz.. then i would just have to figure the correct ram timmings after that.