Set up the Raspberry Pi as a wireless router using the Raspbian OS. The internet connection will be provided by a Huawei E303 USB 3g dongle on the safaricom network in Kenya, though the setup should be similar on most Huawei dongles and 3g networks. The wireless access point will be provided by an Edimax Nano USB Wifi adapter.
Power Source -------->RPI ----> Powered USB HUB -----> 3g Dongle
The USB ports of the Pi seem to struggle to provide the power for a 3g dongle, so a powered USB hub is necessary.
After a lot of reading and messing around, I've come up with a step by step guide for setting up my Pi as a wireless internet router. I use this every time I make a fresh setup of Raspbian, which is a fairly regular event. Stumbling round my latest install like a drunken elephant, it never takes me long to screw something up so badly that it's easier just to start from scratch.
As such, this guide assumes that the Raspbian operating system is 'fresh'. It has been tested with the 2012-12-16 release - as soon as I have the time free, I'll update the guide for the newest release. So, the steps I use to set up the 'Pifi' Router are as follows:
This guide and more like it can be found on my blog.