"Addition released their application iPhoneModem Saturday through the MMi Cydia source. They describe it as "an application for the iPhone that aims at making it really easy to use the iPhone's internet connection on your computer," and they deliver.
iPhoneModem makes tethering a 10 second process. For those of you running OS X Leopard (iPhoneModem is actively working on the desktop client for MacOS 10.4 and Microsoft Windows, as well as a 1.x iPhone version of the app), you simply install their Leopard app (200kb .dmg direct download), open it, and press connect. This will automatically create an ad-hoc network named iPhoneModem on your Mac." To get more information about iPhoneModem head over to ModMyiFone .