Was trying to locate when the ISS would pass overhead tonight (went past around 9:55pm) and remembered Celestia (http://www.shatters.net/celestia) and Stellarium. Stellarium is about perfect for this kind of amateur astronomy - just set you location and you can see what the night sky will be like. 

Try http://heavens-above.com/

+Jeremy Visser Nice. Yeah, that's exactly the sort of thing I was looking for. Most other sites would just give the ISS location and didn't give predictions.