I've searched far and wide and still can't seem to find a real pinout diagram for this board.
There is a 21pin header that is labeled A0-A7 across the top and the side is marked S+G down the side of the three rows. The schematic from their store does show the pins on the Xbee adapter area but not this main connector.
Got a link?
The schematic is 3 pages, have you looked at all of them?
ftp://imall.iteadstudio.com/IM120410001_IBoard/Documents/SCH_IM120410001_iBoard.pdf
Not really sure which pinout you are not seeing.
The A0-A7 pins are the analog pins, similar to A0-A5 on the Uno. The docs state A6 and A7 don't work quite like the others.
The other two pins are for ground and power, useful if you want to use the pins for a servo or sensor by connection via a 3 pin connector.
I documented the board a bit and sent it to them but they didn't post it. The price has not gone down so I haven't bought more than the one I put in my attic project although I really like the xbee and RF24 sockets but wish that pin assignments would be more flexible.
I felt the boards were a good deal to include the Wiznet
As for the schematics I did guess as much but it would be nice if there were a little more info on the pins.
Here is the document I developed. It lists some of the pin info. As I did it several months ago I won't vouch for completeness but it may give you insight other docs have not.
IBoard.docx (699 KB)
It's labeled pretty clearly in the diagram on the page you linked:
http://imall.iteadstudio.com/development-platform/im120410001.html
It calls them "Electronic Brick Connectors", and they provide power for a sensor as well as an analog input. The "top" pin of each column is the Signal ("S"), the next pin is power ("+"), and the bottom pin is Ground ("G")
