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

Features:

Ability to play virtually any video or audio format
DVD playback, with DVD menu support
Picture viewer
Music player
Online media support, courtesy of Navi-X
SD, USB 2.0, SMB, HTTP, and FTP support
Attractive libwiigui-based interface, designed with the Wii in mind

Release notes:

Another day, another release? Hopefully this doesn’t become a trend. Version 1.0.9 has been released to fix the bug with USB drives not showing up. If you’re using the channel, you must be sure to have the latest channel (1.4) installed for this to work.

http://www.wiimc.org/2010/08/18/version-1-0-9-released/