That depends on what kind of phone you have.If you have Nextel I have Webjal(Nextel's program for uploading ring tones to a phone) and I have a program to bypass their password and login stage.If you don't have a Nextel though...I can't help you.
If you have cingular or t mobile, you can make your own ringtowns on certain phones. Sometimes it depends on your phone you can make your own ringtones.
Anybody with an LG phone (most of em anyways) can use Bitpim. Just google it. It's a nice program. You can take pics, vids, ringers, your phonebook, etc. off your phone and vice versa. You just need a USB cord
anyon here ever use xingtone? Its a computer software. you DL on to your computer. your phone has to have email capability. enter the info about your phone. like what carrier you have the phone number and the phone model. then you can take any song that you have on your computer library and cut like 20 second clips. it sends a a email then you dl the clip from the email onto your phone. It only works with ATT, cellular one, cingular, sprint, and t-mobile.