Let's face it, they (the corporate bean counters) want you to buy and download ringtones. But what if, like myself, you have an extensive library of songs and sounds in .mp3 format and you simply want to assign one as a ringtone? Well, you're in luck, here's how:
1. Connect your phone to the PC
2. Open the DCIM folder, then open the folder inside of that (if you took any pictures they will all be in there too)
3. copy and paste your favorite songs or sounds into that folder (mp3 or wma format)
4. Rename the file extensions from .mp3 to .3g2
5. Disconnect from the PC and go to Settings>Ringers>(whatever you want to assign to)>My Videos>Memory Card>(your song!)
Done! Congratulations, you just got one over on The Man.