Dolphin is a Gamecube / Wii / Triforce (the arcade machine based on the Gamecube) emulator. Originally developed by F|RES & ector. Now open source under GPL 2.0 with lots of contributors.

Runs the following types of games:
1. Gamecube Game Disc
2. Wii Game Disc
3. Wii Downloadable Games / Virtual Console
4. Triforce Arcade games

Features:
1. Action Replay Simulator
2. Xbox 360 Controller support, with rumble (KB Plugin)
3. Experimental NetPlay
4. Anti-Aliasing, Anisotropic Filtering (OGL Plugin)
5. Save states
6. Memory Card Manager with GCI memcard export/import support
7. Real and emulated Wiimote support
8. Basic PowerPC Debugger and Log Window
9. DSP HLE and experimental LLE
10. Memory viewer and dumper
11. PowerPC Just-In-Time recompiler
12. WAD Support
13. Some support for Homebrew and XFB Emulation
14. Hi-Res Support, texture dumper, Free Look (OGL Plugin)

Gamecube compatibility is okay - lots of games work, many games don't work.
Wii compatibility is also good - a lot of games do work. Wii emulation generally requires a bit more computing power than Gamecube emulation, though.
Triforce compatibility is not really known yet, but at least one game runs, with minor glitches.

The license of this software is Free, you can free download and free use this game utility software.