If I'm here in the USA I might want to dial a number such as: 858-555-1212.

If I go overseas I guess I'll need to add some numbers/characters at the beginning (such as a +1 or *1, etc).

Does the Treo 600 support an easy way of doing this? I have a Treo 300 and I'm not aware of any such feature. It sure would be a pain to have to edit all speed dial buttons, or to have to manually add them each time I call.