When I was going through my system upgrades (the original Panther upgrade, and then the FireWire cable failure induced reinstall), I was dismayed to find no references to iPhoto in my Desktop prefs. I think this is due to the fact that my iPhoto library is stored in a non-standard location; the Desktop pane didn't seem to see my library.
I tried to fix this in a few complex ways (aliases, symbolic links, etc.), but nothing seemed to work. In the end, the fix turned out to be incredibly simple -- just create any new album in iPhoto. The next time I launched the Desktop prefs pane, all of my iPhoto albums showed up.

