convert mp3 to mp4

Is there a way to convert mp3 (and some wma) files to MP4 type files?

wma and mp3 are Audio formats

MP4 is a Media container format for Movies

Why do you want to convert audio to a blank movie with sound?

or do you mean mp3 to m4a or m4r?

OOPs I am revealing how little I know of Mac formats. What I want to do is to move some older music files (mp3 and wma) to an ipod nano.
Joe

MP3S will work fine on the Nano - no need to convert those. As for the WMA files, I've never tried it but apparently this will do the trick for you.

Just for the record, MP4 most certainly CAN be audio files -- in fact, they are the DEFAULT audio files for iTunes! M4A (the file type you will see on iTunes files) is MPEG-4 Audio, but if you changed the filename to MP4 it would still play.