Daniel Pink gives a great RSA talk about it here. What I particularly like about this talk is, well, the comics of course--it's an animated explanation of why large monetary rewards aren't the motivators people think they are. In fact, as our recent economic meltdown has demonstrated, they produce some pretty nasty results.
He also gave an earlier version of this talk as part of the TED Talks series. There he delved a bit more into the experiments and social science behind the studies.
The moral: pay people enough so that they don't have to worry about money. But just as importantly, give them as much flexibility, purpose and opportunity to grow as is possible. The results are astounding.
Thank you to Tobias Buckell for the fabulous RSA link.