How can I download the themes for my iDVD?

The only way to get all of the themes available is to purchase iLife 09 on disk. (Also comes with iDVD.)

Readily available on eBay.

iDVD is not legally available for download from the internet, discontinued or not. You'll need to do as Ziatron described.

OT

iDVD is not legally available for download from the internet

True, but an interesting subject.

I was in the software business for about a decade, I know a little bit about this issue.

Most people think that software will fall into two categories. Copyrighted, or public domain.

There is also a third category, a bit more nebulous but quite realistic in the real world. That is the category of “Don't Care”.

I own the copyright for various computer programs. I consider this software obsolete and of little value. Nevertheless I own the copyright. Some of this software is available for download on the Internet. But I don't care.

Another example are old movies that are NOT published by any studio. In many cases the production company and producers are dead and any copyright owners (if they can be found) “don't care”.

There are small companies that sell these movies. Their websites usually have a notice stating that they will stop selling the movie if they are notified of a copyright violation.

Please understand, I do not disagree with anything you said above. It can be difficult or impossible to figure out when a copyright has been “abandoned”.

Further, I am concerned about the future availability of used software. Let's say that iDVD was never distributed on an optical disc, but only sold as a download in the Mac store. If that software is later discontinued there would be no way for someone to legally purchase it. In my mind there are lots of negatives of not distributing software physically.