BOSS MSX Frontend
   Frontend for the fMSX emulator.
   http://members.ams.chello.nl/koppejan/

EMUStation
   Universal Frontend, featuring built-in IPS patcher, ZIP support, and Explorer integration.
   http://zerosoft.zophar.net/emustation.htm

Game Launcher
   A universal DOS front end for emulators.
   http://www.dribin.org/dave/game_launcher/

KStella
   A KDE frontend to the Atari 2600 emulator, Stella.
   http://kstella.sourceforge.net/

Kemulator
   A multi system open source frontend for Linux/KDE.
   http://kemulator.sourceforge.net/