Dolphin is an open-source emulator that can run GameCube and Wii games on Windows, Linux, and Mac OS X in high definition. Follow the link to the official Dolphin wiki and check out some other helpful links:
- 1UP: Second Chances: Play Mario and Zelda in HD Today - an article detailing the emulator along with some high-resolution screens depicting the emulator's HD capabilities
- NeoGAF Official Dolphin Thread - discussion and guide to getting started with Dolphin