This collection of sketches and scripts (released on a CC-BY-NC-SA 3.0 license) are designed to work together with the RasPiO Duino Raspberry Pi add-on board as an inexpensive, straightforward way for Raspberry Pi users to get into Arduino programming...
These programs start very simply and build up in a step-by-step way as we go through them. Everything is explained in the (currently 54 page) booklet Learning Arduino Programming with RasPiO Duino...
...which can be found at http://rasp.io/duino-programming/
Assembling your RasPiO Duino is explained fully on the RasPiO Duino Assembly instructions page.
Software Setup is explained fully in both the RasPiO Duino Software Setup Video and the programming booklet.
If you'd like to buy a RasPiO Duino, you'll be able to do that at the
Main RasPiO Duino page
Enjoy :)