You can only change the tags of mp3 files, if you try it on an aac file it won't work - and I can confirm that it still workse in iTunes 9 - I did, however make a mistake - the option is called "Convert ID3 Tags"
Thanks Josef, I didn't realize they called them something different with AAC files.
Do you know a way to standardize them for AAC? I'm getting an error with iVolume saying it doesn't have a iTunesNORM tag... so it won't normalize the song.
I'll take it up with the vendor.... sorry for overlooking the obvious!
The "iTunesNORM tag" error is an annoying limitation in iVolume. When you import tracks to iTunes with "Soundcheck" selected (which it must be for iVolume to work) iTunes analyses the tracks and sets a volume.
iVolume sometimes has trouble accessing this information, and the only solution is to remove the tracks from iTunes, and re-add them forcing iTunes to re-analysis the volume - iVolume will then recognise them.
Sometimes with mp3 tracks, even this doesn't work, and you have to set their ID3 tags to "None" - this quite often wipes out the artwork and other info (Album/artist etc.) which you will have to re-enter.
I had to reconvert my files from AAC to AAC.. (Ha) and the error went away... but it appears that iTunes is creating write protected folders so I had to manually adjust the permissions to Read & Write.
I purposely didn't mention the option of converting the files, because you loose quality by doing this.
If that's not a concern for you - then go ahead.