I have a apple-ified nVidia 8800 gt that has a sometimes annoying fan.

Apparently, some aftermarket coolers exist, like this one, and if one's case is well-ventilated enough, it can even be used fanless.

Has anyone ever futzed with something like this? I assume it isn't altogether much different than putting a fan on a CPU, right?

The other alternative is upgrading to an ATI 4870, but that might not be any quieter, and the apple-ified version is 'spensive ($314 edu pricing).