planetbeing recently let us know he had Android dual booting on the iPhone 2G (the original). He has now posted a picture showing progress on the 3G. The image shows an iPhone 3G booting into a BusyBox / Buildroot shell, and shows WiFi working.
BusyBox is a tiny binary which combines small optimized versions of many common UNIX utilities into one package, which let's the developer interact with the device without having a full GUI environment operating.
He's able to talk to the baseband, although only through the debugging channel at the moment. This means calls can be made.
The to-do list is small now: