I've noticed in DVD Studio Pro that it has a timeline. If your editing is done in Final Cut, what is the purpose of it in SP? Getting ready to get into Studio Pro and am wondering.

I've never used it, however have you seen the "tours" on Apple's website?

http://www.apple.com/finalcutstudio/dvdstudiopro/quicktours/

The DVDSP support forum on Apple's site might also be of interest:

http://discussions.apple.com/forum.jspa?forumID=952

The timeline is used for placing markers, combining multiple tracks of video, audio and subtitles, adding buttons that appear during playback and sometimes stringing already encoded clips together. It's no good for editing in the typical NLE sense, but you can do quite a bit in the DVDSP timeline. It's essential if, for example, you want to make a multi-angle DVD. I imagine it's also in DVDSP because it is familiar to editors, and I think that's the market segment the application targets.