It depends what kind of phone you have, but if you have a Razr then these steps will help.
First turn on Bluetooth on the Razr (ships disabled by default to conserve battery power):
Select Menu –> Settings –> Connection –> Bluetooth Link –> Setup –> Power
Them, for transferring ring tones select Menu –> Multimedia –> Sounds
Once you've found the ring tone sound that you want to transfer, select Menu –> Copy –> [Look for devices]
Once it finds your computer, you can copy files over.
There are also programs in the article below that'll let you copy files over in one shot (as opposed to having to do it one at a time with direct Bluetooth).
