International Date Line http://geography.about.com/od/physicalgeography/a/idl.htm (Matt Rosenburg)
Explains the date line.
World Time Zone.com http://www.worldtimezone.com/
Interactive time zone map.
World Time Zone Map http://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/world-tzones (U.S. Naval Observatory)
