All I had to do was copy a ringtone I wanted and paste it in my windows folder. Then I can access it from the notifications menu. I have a bunch left over on my storage card from my Voyager, not sure what format there in.

Re: How can I use a custom ringtone for my text messages on my mogul?
 

I have the HTC touch pro (the sprint version of the mogul) and to get the custom ringtones, forget about the .wav converters. Just copy the mp3 and paste it into your windows folder. Go to Start-programs-file explorer. Under, My Device, open the Windows folder and paste the mp3 in there. It should make it an available ringtone for your texts.
I will tell you to crop it though. There's no way to stop the ring while talking on the phone, so if you set the whole song as your ring, it will play the whole song in your ear while you're on the phone.