Are you using windows or mac?

To check whether all songs are mp3, go to edit view options & choose to show 'Kind' & that will show a column in the main library which will show whether they are mp3, or whatever.

What do you mean iTunes Music Lib. is missing songs? Do you mean the songs are on your iPod but not in your iTunes library? Remember to select Library at the top of the playlists to show the entire library listings & not just a playlist listing.

Oh Only a Hobo beat me to it!

Actually I was of the impression iTunes for windows did import wma. But I could be wrong.
* Late Edit: See under WMA listing here: http://forums.ipodlounge.com/showthr...threadid=38962