Sorry for the delay in replying. Yes I was using TVOut through the Pioneer iPod cable. The app to connect to my PC/Macbook Pro is called JaaduVNC but there are other (cheaper/free) VNC solutions out there. This was all done on 3G however (requiring the 3G Unrestrictor for the Slingbox).
I have not messed with any other "video out" apps besides TVOut, but man was it a pain to get the sizing/location of the screen/touchpad set up. For my iPhone 3GS with the Pioneer iPod cable my approximated TVOut settings are as follows: Screen Position - H: 85, V: -20, Screen Size - H: 1.5, V: 1.1,