http://www.avery.com has word templates for all of their products which include dvd covers.

They also have some free software called DesignProLE. This is intended to be used with their pre cut labels and such but if you are willing to use a razor and straight edge...
http://www.avery.com/us/Main?action=soft...ftwarecode=3202

Lastly they have a fifty-something buck DesignProDeluxe available at avery.com.

Oh, they also have some kind of online label designer which I haven't checked out.

EDIT: The downloads don't work well in FF. (read not at all)