iDVD is Apple's free DVD editing program. Yes, it _should_ be free. I guess it wouldn't surprise me, though, if you only get it with a computer that has a SuperDrive. Bummer.
If Apple made iDVD easy to get, then other Mac users could join the DVD revolution with an external burner. I can't imagine that cutting into sales of high-end Macs, but then, that's not my job.
-Rob