OK I was checking out my kids Skylanders game, and got curious as to what it was running under the hood. Stumbled on the articles below (well forum posts).
Turns out there is a tool you can use that uses hidapi to read/write to the skylanders (to up there levels). The whole thing uses a MiFare read/writer and the characters themselves store the data. Going to have to do some more looking into this in the future.
http://www.backtrack-linux.org/forums/showthread.php?t=47551