mp3 and wma can be imported into World Editor if it is not wrong.
You can import any sound into World Editor with that format.
(Becareful Your Map Size, BNet does not allow map with more than 4mb)
If you have CS, try to import some of the sound from CS to WE, that is fun.
Well since it's you, you will understand. I'm searching for a song to play while you play my escape. It might not work though (ill test it and see if its a cool touch or annoying)
It isn't legal to use these unless you pay to download them, you could always buy a CD of what song your looking for and convert the .wav to a .mp3 to reduce file size.
Please, do stop discussing about downloading music, it is illegal and TH don't support that (unless I'm wrong?). If you want to discuss music, create a new thread in the music forums, as long as the content is legal. If you want to ask about music formats, head to the general tech forums.
Anyway, as for iTunes, just follow these steps to get your music in MP3 format (supported by WE).
Open iTunes. Open Edit in the toolbar at the top of the window, and click on "Preferences", or, simply when opening iTunes click on ctrl and "," together. You should now have a new window opened. It will have a toolbar of its own. Click on Advanced in that toolbar. Once again, a new, smaller toolbar will appear under the last toolbar, click on "Importing" in that toolbar. Now, you should have an option saying "Import Using" select the wished format (MP3 Encoder).
By the way, as far as I know iTunes doesn't support MP4.
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.