I will add to the above...It is the VERY Best VNC app for couple reasons. Works almost instantly on WiFi, Works fine over Edge network (i have original iPhone) so I think that your 3G will be just fine. Even with only 2 bars on edge it loads my computer, slowly but usable. The last and very important reason is that their customer service is OUTSTANDING and almost instant. They are still working on phone support but they read and respond to your emails within 15 minutes. They will assist you with in depth instructions to get you up and running. I highly recommend Teleport!!!
Gary