Anamorphicizer
Export your video from FCP like you normally would for going to iDVD. Drag and drop it on the Anamorphicizer. You'll get a second file in the same folder with Anamorphic added to the file name. Drop that in iDVD!
Anamorphicizer
Size: 58 KB
Should work with Leopard, as well as Tiger, assuming you have a recent version of Quicktime.
Inverse-Anamorphicizer
Size: 58 KB
Same as the other, but backward. Get it?