ElfYourself.com was created for OfficeMax during the 2006 and 2007 holiday seasons by agencies EVB San Francisco and Toy NY. I'm not sure what program was used, but I can tell you the site was a huge success, reaching "one in ten Americans," according to Nielsen Online Strategic Services. Best of luck with your search.
I used this online program to create a neat "Elf Yourself" Xmas card. I believe Office Depot was the sponsor. Does anyone know about this or similar software which may be available? I would like to make my own personalized animations.