This page will give you a slide show of youtube videos based on your iTunes library. To use it upload your iTunes library
and watch. The video chosen is proportional to the number of track you have for a given artist. That is, the more tracks for an artist, the more likely it is that artist will be chosen. You can also click 'next' for the next track, as this is far from perfect. Also, Internet Explorer doesn't seem to like this, which won't change, as I don't like it.
Or just load a comma-delimited list of bands
For mac users this is usually located in
~/Music/iTunes/iTunes Music Library.xml
For windows folks it's in
My Documents/Music/iTunes/iTunes Music Library.xml
For Linux folks, I'm guessing the same as mac people, but don't hold me to that.