Code searching sites seem to be popping up on my radar alot lately. I've found
http://www.koders.com useful in the past and
Jase mentioned jexamples today which searches open source project code. The latest one I've come across brings back examples from books:
http://www.codefetch.com/. Time will tell who will be the
Google of them all. Actually, that's one thing
Google haven't done... yet!