Having trouble making a ringtone?

Ok, so instead of just recording part of a song to use as a ringtone, I'm trying to edit a song with audio editing software and use that as a ringtone (it sounds clearer). Every program I try exports the file as a WAV and once I get it on to my phone (it gives me the option to convert the file to a WMA, which still doesn't work) it will play but my phone won't let me set it as a ringtone. Are there any free programs I can use that will let me do this, or is there a way I can save it to a different file format that will allow me to set it as a ringtone? Thanks. Also, my phone is a Samsung Eternity if that helps at all.