Well, we decided to use our SD card from our digital camera with the Wii. I wasn't sure what setting my wife was using, so wasn't sure our Wii would read the pics...but it did! From there we've been exploring the 4 areas: Slideshow, Mood, Doodle, and Puzzle.
What can I say? They're all fun - the slideshow is probably the coolest, in that it comes with some background tunes but gives you the option to add your own in an mp3 format. My four year old is having a blast making a puzzle out of her own picture and then putting it back together. It gives you a finishing time and if it's a record (of course the first finishing time is), then hands appear and clap while celebratory music plays!
Knowing full well that this system is still in it's infancy...if this is truly the tip of the iceberg, one can only wait in anxious anticipation as to what awaits us in the coming couple of years.