it might be hidden in the multitude of software restore disks (my dual 1G came with iDVD installed, but the only way to recover it was to run the 5 software restore CD's to return a partition to it's factory state). I've heard you can use an app called Pacifist to look inside the disk images (each CD has a partial disk image on it, img I think). Also, I've heard you can copy each partial image to your hard drive and then open the first one and the full image will be mounted, then you can root around in there. I haven't tried either of these, as I haven't had occaisson to use iDVD since I first reformatted.
Or, I believe you can buy an iDVD 2 update disc from Apple for US$20, and the disk is actually a full install. this is also unverified
there's also no guarantee that iDVD 2 will run in Jag...