How can I use my music on my Htc phone as a ringtone?
If you want to make a song into a ringtone there is an app called "Ringtone Maker" that lets though cut and edit a song and make it into a ringtone. Or you can use Zedge and find the song you are looking for.
get an app for it
I use the zedge app to do that - get from google play store