I found some time to improve my MP3 library. Now it allows to read and write! ID3v2 Tags.
I`ve not implemented everything but you can read basic information and edit it. You can even select a jpeg or png file that will be embedded into the mp3.
You can still trim the mp3 with the timeline. ByteArray and AIR kicks ass!
Sources will be released as soon as i find the time to clean up the code and implement some more functionality.