Babygimp! I never used but the name is nice :)
http://wws.mathematik.hu-berlin.de/~lederer/Babygimp/index.html and the snapshots too http://wws.mathematik.hu-berlin.de/~lederer/Babygimp/screenshots/index.html I once used an icon editor (very simple one) that came with the unofficial gameboy development kit for Linux, but don't remember the name. Maurizio Umberto Puxeddu.
