You can find a list of the albums that used to be available from the theme park kiosks in the 10/8/06 MouseTunes shownotes:
But that's "used to be available...."
These albums are not yet available on iTunes.
To check what Disney music is available, look for an "eye" icon (in the current version of iTunes, look in the window's lower right corner. Click on it and you'll get the option to choose from a genre list in the left column of the resulting window. Look for "Disney."