Just because Steve has promised to give us an SDK in February doesn't mean TUAW's own Erica Sadun is giving up on us. She's still going strong on getting more and more functionality onto the iPhone as we speak. Case in point: her new SendSong, which is updated from before to work with 1.1.1 and the latest ringtone developments.
She warns that it's still pretty "flakey," but the idea is that you can click any song in your iPhone's library, and then choose to send it by email to someone else, or (and here's the kicker) automatically make it a ringtone. Give it a try, and let her know how it works. Official iPhone development may start in February, but unofficial iPhone development continues.