SparkFun (www.sparkfun.com/)—A popular USA supplier for Arduinos, shields, electronic components, and all things DIY. Lots of information can also be
gleaned from the SparkFun message board forum and the product comments.
Adafruit (www.adafruit.com/)—Another popular USA supplier for Arduinos and DIY electronics. Like SparkFun, Adafruit also has great tutorials and online
forums. Highly recommended!
SK Pang Electronics (www.skpang.co.uk)—UK supplier for Arduinos and DIY electronics.
Cool Components (www.coolcomponents.co.uk)—UK supplier for Arduinos and DIY electronics. Subscribe to their newsletter for updates.
Bitsbox (www.bitsbox.co.uk)—UK supplier of a range of electronic components.
Proto-PIC (www.proto-pic.co.uk)—UK supplier for Arduinos and DIY electronics.
oomlout (www.oomlout.co.uk)—UK supplier of Arduinos, electronic components, and kits.