Audacity is a tad simpler. Well, okay so you also need to download some kind of LAME library to do the encoding/saving off.
Of course, bitpim is going to be needed to make/transfer to phone the actual ringtone, but it's all free. That's my method at any rate. Audacity to edit down, bitpim to encode to ringtone/transfer to my phone. Verizon VX8300. If I can do that with a Verizon phone, it should be even easier with the providers that don't throw up roadblocks and try to nickle 'n dime you to death.