Your going to be right around the $100-$150 range for a quality PSU to do SLI (which I don't recommend). Here are some to consider for your proposed SLI rig:
PSU - $100 shipped - $10 MIR = $90! Good solid PSU for the $, hard to beat.
Corsair 520W SLI Certified Modular ATX Power Supply - CMPSU-520HX
http://www.buy.com/prod/corsai...loc/101/203270716.html
PSU - ~$125 shipped Good solid PSU, straight from OEM and cheaper than Newegg
ULTRA-QUIET PSU: SILENCER® 610 EPS12V
http://www.pcpower.com/product...roduct.php?show=S61EPS
PSU - $100 shipped , hard to beat for this price.
Antec NeoPower NeoHE 550 ATX12V 550W Power Supply 100 - 240 V UL, CUL, TUV, CE, FCC, CCC, CB, C-tick ? Retail
http://www.newegg.com/Product/...x?Item=N82E16817103941
PSU - $130 shipped Nice a quiet and cheaper from OEM, not from newegg.
ULTRA-QUIET PSU: SILENCER® 610 EPS12V
http://www.pcpower.com/product...roduct.php?show=S61EPS
Any of these will do, but most people will recommend a 650w or more for 8800gtx's SLI'd. Here is a link to show you how well a quality 380w PSU can power a OC's e6600 w/a 8800gtx system! Not that I would bet my expensive system on it, but you can see what were talking about.
8800gtx on 380w PSU!
http://www.overclockers.com/articles1452/
PSU - $49 shipped! Can power 8800gtx and an OC?d e6600! See link above for proof!
Antec Earthwatt 380W P/Satx 12V v.2.2 80MM P/S2 Fan 80-Plus Certified - EA380
http://www.buy.com/prod/antec-...loc/101/203477214.html