The most popular magazine for amateur astronomers, and a fine source of current and general astronomy information.
A marvelous NGO helping thousands around the world with solar cookers, education, research, project support and government interface. For so many issues around the world, the solution truly does come up every morning. Give until it hurts!
A US based group with extensive information and publications available.
A UK based page compiling a lot of useful Sundial information
A broad study of sundials, their history and links for further information. Pretty rich in details but quite understandable.
Wikipedias thorough explanation of all things Sundial
A great time resource with info on calendars, Sun and Moon positions, eclipses, calculators and much more.
A nice printable version of the Equation of Time. This gives the corrections from clock time for each day of a given year so you know when to actually record a mark.
US Government resource on all things time.