I was in the process of converting a few albums to AAC in order to save space but for some reason iTunes won't play my music files even though i imported them from itunes itself. When i import them from the cd i encode at 256kbits as i do with my mp3 files, the files do play as mp3 from my music cd so it isn't a copy protected one or anything. the files play as mp3 but not aac basically. But (and i don't know if this is it) the AAC files extension end with m4a and i was thinking this should be .aac. Am i wrong do you know whats going on in general? I'm using itunes 4.0 on an ibook running on OSX 10.2.6. To also note, itunes does read the file, it just doesn't play, i renamed these aac files with mp3 rage as well.