To cut my teeth I may write a small app to find a number in your contacts database. Unless I'm wrong, this is currently achieved by either going through all the entries, or typing the number in and dialling (at which point the phone will show a matching contact).
I think it might be useful when checking home phone bills against the 7650. Anyone agree? If so It'll probably take me a few weeks (small task, but I'm kind of busy at the moment)