If you play the files with some sort of programme which displays the id3tags, such as iTunes, you can open the id3 tag and delete the album art.
This works on Mac and I assume it also works on windows.
alternatively you can use a stand alone id3 tageditor, which, as Sleepless says, you can Google for.
I notice there is an ad at the top of this page for "fixtunes" which looks suspiciously like a rip off of iTunes. It may be good .. but I don't automatically trust advertisements I see on this site, and nor should anyone else. The ads are not, and cannot be, vetted by the forum administration on a regular basis I'm afraid
