If you get DVD Studio Pro (from Apple), a word of warning, it's the least intuitive Apple program I've ever used. I picked up basic Final Cut functions without missing a beat, but DVD Studio Pro, doesn't work much out for you.
I've got it working now, but I was stuck with bit rate and Photohop layered file button problems for a week. I'd never read the manual on a program until Studio Pro.
Dvd Studio Pro is good for what you're doing. Has a moderate learning curve until you try doing more complex builds. Otherwise iDVD might work for you which is free with new Macs or is included in the iLife Suite. That's of course assuming you're on a Mac.