Alken MRS
Detailed guide to TV broadcast standards worldwide that includes information on voltage and UHF/VHF frequencies, in addition to the colour system used.
http://www.alkenmrs.com/video/wwstandards1.html

Audio Video Affair
An online guide to different audio and video file formats, and how to get the most out of them.
http://www.audio-video-affair.com/audio-video-glossary.html

High-Tech Productions
PAL, NTSC and Secam system information, global and American TV station links, video glossary, video tape times, tape and VCR tips, DVD and widescreen information, and more. Just look under the section marked "More to Explore" on the right hand side of the page.
http://www.high-techproductions.com/main.htm

World Video Formats and Standards Conversions
A quick-reference guide to television broadcast standards around the world.
http://www.video-pro.co.uk/worldtv/index.html

Worldwide TV Standards
An explanation of why different TV standards exist, TV system comparisons, broadcast system details, video formats and FAQs.
http://www.ee.surrey.ac.uk/Contrib/WorldTV/