Arduino & Raspberry Pi
Bramble Pi : Our local Pi cluster
Main Reference pages
Basics of Circuits Nice explanation of Pull-up and Pull-down etc.
Adafruit Arduino Learning pages: Contains projects.
LadyAda's Arduino Tutorial: Suitable for students. Should be first port of call.
UBC's Arduino module page: Contains some useful links, particularly to Youtube movies created for this module.
UC Hobby Nice site for coding examples, project tutorials and other stuff.
SCM lab & my projects
Raspberry Pi Wiki: Lots of information here.
Cooking Hacks' Pi to Arduino shield: Main page for tutorial/libraries etc.
LadyAda's Raspberry Pi Learning page: See first few pages for Pi setup instructions.
Gordon's Raspberry Pi page contains cool information on the WiringPi library with lots of information about Arduino-type connections. This library also covers the PiFace board. Looks like a cool site!
LadyAda's Raspberry Pi Learning page: Lots of projects and tutorials here.