http://www.cleaningdigitalcameras.com/howto.html

That's what I use, along with a 2oz bottle of the Eclipse E2 fluid (expensive/overpriced, but a one-time purchase).

Works very well, but generally takes a few iterations to get it reasonably spotless.

Don't be anal about it -- just get rid of the larger blotches and call it done. Otherwise you'll be there for hours and hours. It usually takes me about eight passes, though there's very little improvement after the first three.

And it's not really the sensor that's being scrubbed, but rather the glass (IR filter) in front of it. Tough sucker, that thing!

Cheers