Can Custom Message Tones be made?

[BergerFan]

Thanks to some guys in another thread, I've been able to make my own ringtones. I was wondering, if it's possible to create custom message tones as well?

 

[TEG]

You can. They must be Aiffs and installed via scp once the phone is Jailborken.

TEG

 

[marykay9507]

If your phone is not jailbroken, it is not possible, right? What are the chances this could change in the future??