How to change download file types

[slainte]

I've been using Limewire for a while downloading mp3 files with no problem. Recently, I downloaded a wma audio file and when trying to send it to itunes it asked me if I wanted to convert it. Now, almost every file I try to download is an au or wma file instead of mp3. Is there a setting that I can change to get back to the mp3 file formats? Any assistance would be very much appreciated.

Thanks,

Slainte