The charts below outline what happens when you change the camera settings. The exposure triangle means, when you adjust one setting it can effect the other two.
Outside of Auto - Useful Canon site to test your manual exposure skills
Digital Photography Basics - From Olympics photographer Alex Buisse
Phlearn Various tutorials relating to digital photography and photoshop. Search for the free stuff
Digital Photography School - All sorts of free resources and technical articles
Photography Tutorials - Lots of tech tips covering a wide range of Photography
The Strobist - tips on using flash lighting
Pixels after Dark - video lecture with various night shot examples
Studio Lighting - Albert Watson uses flash
STUDIO PORTRAIT GUIDE - Good guide for diagrams and effects