A friendly commenter noted in my last post that the guys over at Digital Railroad have also just released an export plug-in for Aperture.
You can read about it and download the plug-in for free here.
Thanks to Eberhard for pointing this out. Next week I am planning to spend some time comparing the plug-ins for both PhotoShelter and Digital Railroad. I have used both services in the past, and I am still having a tough time deciding which one is better. Perhaps a little plug-in shootout will help me see the light.