Sparkfun flashlight kit tutorial web page - explore
the different sections on the right-hand side of the page.
Adafruit soldering tutorial video
Adafruit desoldering tutorial video
Soldering is Easy comic by Altman, Nordgren, and Keyser
Plusivo soldering kit manual
Adafruit soldering preparation page
Adafruit good solder joint page
Adafruit common soldering problems page
Seeed Studio common soldering problems page - note that nearly every picture on this page has been copied from some other website. Nevertheless, it is a useful collection.
Sparkfun soldering tutorial web page