I used Image Capture to import photos to iPhoto, with the option to delete the photos from the camera after import. Image Capture finished the import with apparent success, but iPhoto did not show the photos.
I found them in /Private/tmp/Image Capture_Import.xxxxxxxx/, where x's indicate a sequence of digits and numbers (which I imagine changes each time).
[crarko adds: I haven't tested this one. I just import directly to iPhoto without using Image Capture as an intermediary.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20101215095521610