Yes it will fit your video card.
The concern that i have about this heatsink is that it recirculates the air back into the case and blows the hot air into the motherboard, rather than blowing it out the back. It also heats up the rest of the system. HOT HOT.
I have one now and it fitted perfectly. I hard wired it to a molex so that it would run at a constant 100%.
It certainly does make raise the internal temp so I have fitted a fan below the graphic card as an extractor and it seems to be working OK. Im still able to run my 6600 at 3.1 on stock cooling 34 idle - 50 load (but with all my fans running turned upto 100% my case sounds like a hovercraft)
My GPU idle temps have dropped to about 34 deg C and I can clock upto the max that catalyst offers now (690/ 950 I think) however at that GPU clock my 36marks score drop. I find I get the best scores at about 668.