I do that. I get the song in MP3 form then open it up in editor, my I suggest, Goldwave. I clip it to the part I want. (Usually about 20 or 30 seconds.) Remember the longer the larger the file. I save it in MP3 form. I take out the card of the phone, connect it into my computer and then copy the file into the card. Put it back in my phone and set it as my ringtone.
The v360 has a TransFlash card so there you go.
Get Goldwave here!