Some links to interesting and useful pages we have found that you might like too.

http://www.allaboutcircuits.com/ : This site provides a series of online textbooks covering electricity and electronics.

www.luckylarry.co.uk : This guy seems to  have done everything from 3D Sensor Data Visualisation using an SRF05 to building his own shakeable dynamo

www.discovercircuits.com/index.htm : DiscoverCircuits.com, has 30,000+ electronic circuits, cross-referenced into 500+ categories.  We have searched the web to help you find quick design ideas.

www.learn-c.com : This site is for anyone who is the least bit curious about monitoring and controlling such things as motors, lights and switches, or recording and playing everything from sound to the arm position on a robot.

www.coolcircuit.com/gadgets/category/arduino/

www.hobbyprojects.com: Hobbyprojects.com is a collection of links to 1000's of Electronic Circuits, schematics, online tutorials to find quick solution for electronic design problems. New circuits and/or links are added regularly as a resource for beginners, hobbyists, engineers, inventors and consultants.  Let us know what is missing or if you have a circuit to include in this collection.

http://shieldlist.org/ : Pin usage details for 226 shields from 98 makers, and counting!

http://www.dream.fr/index.html : Audio technology.

http://www.appliancepartspros.com/electric-hobby-projects.aspx : A nice resource on electronic projects, thank you Brian.

http://www.utwired.engr.utexas.edu/rgd1/lesson01.cfm : Some electronic tutorials.

http://www2.its.strath.ac.uk/courses/c/ : Handy C Tutorial.

http://tronixstuff.wordpress.com/ : Regular articles are published about many things, including analogue and digital electronics, electronic kits, part reviews.

http://www.digikey.co.uk/PTM/PTMMaster.page?site=uk&lang=en : Product Training Modules.

https://sites.google.com/site/ioiobookcom/home : This is the web site for the book: Making Android Accessories with IOIO by Simon Monk.