If you've got a full cover art library in iTunes, you want to show it off in iChat! Here are the basic steps which I recently blogged for myself:
set theAlbum to ""
set theData to ""
tell application "iTunes"
set theAlbum to album of current track
set theData to (data of artwork 1 of current track)
end tell
set theTiff to giconvert theData type "TIFF" resolution {32, 32}
tell application "iChat"
set status message to theAlbum
set image to theTiff
end tell
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030825110446769