One of our members, Pin, just pointed out a little note on the official Wii homepage that makes mention of upcoming changes to the Wii’s Photo Channel. Changes include adding support for MP4 AAC files at the expense of dropping MP3 support. These changes will be present in the 1.1 version of the Photo Channel and will be included with all new consoles sold starting in early December.
If you use your Wii for MP3s, then you may want to hold off on the upgrade as it can’t be undone. I personally didn’t know this functionality even existed so I won’t be crying, but some of you might.