iTunes config & Backup software for Mac

Hi. I'll be using a MacBook as a music server only, which I'll purchase next week w/ Leopard installed. Couple of quick questions.

1. Because I'll need at least 230 gb for music, I'll have to put my iTunes library on external drive. Is it easy/straight forward cofiguring iTunes so that it knows I want my music library on external drive?

2. Because music will be on external drive, I'll have to back up that drive to a second external drive. (The internal drive on the MacBook will just be OS programs/files.) If I'm interested in backing up music library only, anyone know if Time Machine lets the user have a bit more fine tuning control, that is, not a plug and play, but a directed backup?

Thnx.