1) Move them to your SD card... then remove the SD card from your old phone and put it in the new phone.
2) Connect your old phone to your PC, move the files to a temporary place. Then connect your new phone and transfer them to your new device... usually your SD card is good for all ringtones.
3) Email them to yourself... leave the email in your inbox until you get your new device, then open the email and download them onto your new device.