WiiMC (Wii Media Centre) is an open source media player for the Nintendo Wii. The GUI is powered by libwiigui.

Features:

Attractive libwiigui-based interface, designed with the Wii in mind
Most essential difference from MPlayer CE and the like: completely GUI based, no fiddling .conf files should ever be necessary (except for on-line media)
Picture viewer
Music player
On-line media support
FAT32/NTFS from SD and USB 2.0 (FAT32 recommended)
Network playback via SMB, HTTP, and FTP
Multi-language support: Chinese (Simplified and Traditional), Dutch, English, Estonian, French, German, Hungarian, Italian, Japanese, Korean, Polish, Portuguese (Brazilian), Romanian, Russian, Spanish

Changes:

Subtitle color/size adjustment
Added checkmark next to viewed files
Added sleep timer
Improved device mounting
Improved stability
Fixed artifacts issue with online media files (VP6 codec)
Synced to MPlayer r31303
Added option to auto-play next video
Add GIF image viewing
More codepages added
Thumbnail support for online media (Navi-X)
Hide folders beginning with ‘.’ and ‘$’
Added screensaver
Add ability to view PNG’s over 1024×1024
Added theme color options
Add more seek time options
Language updates

http://wiibrew.org/wiki/WiiMC