Theres a website that allows you to upload a song, select the chunk of it that you want as your ringtone then converts it to .QCP
I know for a fact it works for Sprint 3G phones since i've used it myself. It should also work on Verizon's Samsung and Sanyo models. If you know the extension of your ringtones is .QCP it'll work.
Suggestion: If you use this program I suggest making the file louder before you upload it, especially on Sprint phones.