The boards included are:
The LED board, three LEDs and a button with assembly instructions and demo code on MyPiFi.net
The second board is the LCD add on module so you can add any hd44780 compatable board eg 16x2 or 20x4 LCD to your project and again comes with assembly guide and demo code to get you started, all you need is to buy a LCD screen to plug into it.
The third board is the 10 LED board, this can be used with the Raspberry Pi or any other GPIO board like arduino with jumper wires or with a port expander board like my forth board.
Then we have the forth board, this is an in/out port expander for controlling things like LEDs via the SCL and SDA pins freeing up many of the other GPIO pins so you can add more to your projects and like with all my add on boards comes with extended GPIO headers so you can still use the GPIO pins.
All common kit form starting at £6 each or all four for £18 on eBay. http://pages.ebay.com/link/?nav=item.view&alt=web&id=181629776059
Here are just a few people showing theirs on Twitter.
I also do discounts to code clubs and Pi shops if you are ordering in bulk too, just contact me for further details.