Need "dbpoweramp" Type Convert From * To M4a/m4b

Hi guys.

Back again with yaq. I do use iTunes/ipod and m4a/m4b quite a lot and don't want to give it up. In my unfortunate Windows world (downgrade from Vista to Xp!) I use dbPoweramp to convert files from mp3/flac & co to m4a.

Is there anything that can do this? Also is there a way of getting Banshee to play m4a/m4b's? I know that one day there will be something very iTunes like for Linux, but until that day I will have to keep using Windows to maintain my pod.

Thanks in advance.