Call fowarding or not to foward

i have my asterisk server colocated runnig Asterisk 1.2.1.

I have it set up so my voip number when somewone calls it it is fowarded to my cell phone. I want it so that when people call my voip number my cell phone is called but not connected if say i dial a 9. I also want to set it up so I can call the number can say press a 5 to be dropped into a the IVR.

Is this possible? How woudl i go about settign this up?

some links for you … +follow+me … s+ivr+menu