I don’t recommend doing this as it may actually make your phone unusable. I recently acquired an iPhone (November 2008) and have been itching to mod it a little bit. No, I haven’t tried the jailbreak technique as I prefer to keep everything simple on my phones. But as soon as the warranty is up, you betcha.
Anyway, I just signed up for a service called TrapCall (TrapCall.com) and it required me to setup my phone to do automatic forwarding of voicecalls. So I decided to write down the steps required to undo and redo this setup (in case this company goes bye bye).
All you have to do is dial *004*18669676590*11# and hit SEND!
All you have to do is dial ##004# and hit SEND!
That got me to thinking, what if I typed in 1800XXXXXXX*11# instead? Can I actually get this to forward anywhere I want? That’s pretty cool actually.