Migratr is a cool little Windows freeware program that lets you bulk move your photos between different online photo services. Currently supports Flickr, SmugMug, Picassa Web, Zooomr and 23HQ and the author is working on Yahoo! photos. Needs .NET. Neat!
Users going between SmugMug and one of the other services should be aware of a slight difference in how the services organize photos. Flickr and 23HQ enable one photo to be a member of multiple photosets. These services can be considered “Photo-Based”, wheras SmugMug is “Album-Based”. In SmugMug, a single photo cannot be a member of multiple albums. Instead, Migratr will automatically upload the same photo to different albums.