Did your razr come with a usb cable? That would be one way to do it. You would have to use a program like p2k to add a file into your sounds folder in your phone. Or maybe a bluetooth adapter but I've never tried it that way.
The way I got "24" ringtones onto my Motorola Razor was to go online with the phone, key in the web address of the MP3, and my phone automaticaly downloaded it. Not sure how other phones do it, but you might want to try that.