Gambatte is an accuracy-focused, cross-platform Game Boy and Game Boy Color emulator. It is based on hundreds of corner case hardware tests, as well as previous documentation and reverse engineering efforts. The core emulation code is contained in a separate library back-end (libgambatte) written in pure platform-independent C++. There is a GUI that uses Trolltech's Qt4 toolkit (gambatte_qt), and a simple command-line SDL front-end (gambatte_sdl). The GUI front-end contains platform-specific extensions for video, sound, and timers.
Game Launcher is a cross platform, universal front end for emulators. The main goal is to provide a user interface that is easy to use and attractive, yet does not look like a traditional user interface with windows and such. Game Launcher should work with any emulator, but it has been known to work with MAME, Nesticle, RockNES, zSNES, snes9x, Callus, Stella, z26, and Versions are available for Unix, DOS, and Windows.
Gelide is a configurable multi emulator and multi system front-end that lets you manage any kind of emulated system (PC, console, arcade, etc.). Gelide lets you catalog and launch any game from any existing emulator under GNU/Linux. You can configure any emulator with command line parameters support.