I was running a quick errand earlier this evening when something hit me. Since the iPhone SDK does not allow developers to run code in the background (ie when music is playing), that means no one can create a Last.FM iPhone application that scrobbles what I listen to on an iPhone or iTouch.
Talk about a missed integration opportunity. How cool would that be to do "live" scrobbling from your iPhone or iTouch? Sounds like a worth while feature to me.