I know there are a few apps that allow a jail broken iPhone to tether over WiFi to a computer so the computer can use the iPhone's 3G. What I want to know is if anyone knows of any open source apps that do this, or partial code to handle the majority of this that I could make in to a minimal app? I don't want to jail break since I do official development, but would like to be able to compile and sideload an app on my personal phone to do this. Even without jail broken privileges an app could use an existing wifi connection (adhoc created by the computer) to share its 3G.