Two new guides have just been posted in the Tutorials and Guides section.  One of them is a serial cable guide which shows you how to make a USB to serial cable form a cell phone data cable.  The other guide is just a general guide showing how to actually connect to the Fonera after you have made your serial cable.  It also has pictures of the serial pinouts for the Fonera 2100 and 2200.

Cell phone data cable USB to serial guide
Connecting to the Fonera via Serial