iPod Artwork

Go to "get info" for the song/album then choose the artwork tab and then delete.

I think you need to do this from iTunes. Just cut it from the little artwork window in the lower right corner (you may need to use the show/hide artwork button) or use the song's Info window (under the artwork tab for one song, for multiple songs just click the artwork checkbox to remove artwork from all those songs).

Edit: Beaten... by seconds...