I had posted about the problems I've had with creating custom ringtones on my iPhone. Aditya suggested trying out iPhone Ringtone Maker.
After downloading the Mac version, I had a few problems that were fixed after I wrote to their support. I tried creating a couple of ringtones. They were much better than the ones made by GarageBand.
They were not what I would have liked, however. The quality is still not 'perfect' - something you would expect from Apple. But it is vokay.
I went ahead and bought the full blown version yesterday - not bad at $7.50.