I have to say that I think the idea behind Denver-based PocketFuzz is pretty cool. Take any MP3 and upload it, then select a portion of it. Then send it to your phone as a ringtone. Neat.
A band can also upload a song and make the PocketFuzz ringtone available for download by fans. Then they can stick a link on their MySpace profile for their fans to grab the ringtone, and get a portion of those revenues.
My quick googling found a competitive service called MyxerTones and I found a MySpace based artist profile using that service as well. I also found some software for doing this on your desktop called ZingTone as well as others.
I was curious about this so I chatted with Daniel Newman of id345 (the company behind the fuzz as well as other stuff). He told me that the service is getting a fair bit of pickup with more than 500 artists participating with thousands of songs so far.