http://www.mp3-box.org/aac-mp3/
How Do I Convert My MP3 Files To AAC?
I heard that i could play music on my wii using the photo channel i have 1.1 and aparentley i can only use AAC files with 1.1 and theres nowhere that i have found to convert my MP3 Files to AAC.
you can do it in iTunes, which is free to download
Rip Music CD to MP3 AAC OGG FLAC – Sound Juicer – Ubuntu Linux 8.04