[Discover] SparkFun Electronics - Relay Tutorial http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=119
(electronics relay controller datalogger) 
[Discover] usb switch on Flickr - Photo Sharing! http://www.flickr.com/photos/simplesimon/163384848/ (solidstate usb relay switch)
[Discover] Industrial Control - Bulletin 700-HA Tube Base Relay http://www.ab.com/en/epub/catalogs/12768/229240/229266/229643/229691/tab3.html (relay)
[Discover] Relays http://www.bcae1.com/relays.htm (automotive electrical reference electronics)
[Discover] Panasonic 12VDC relay spec sheet http://omicron.octopart.com/Panasonic__CA1-DC12V-N__0.pdf (relay specsheet)
[Discover] usb switch on Flickr - Photo Sharing! http://www.flickr.com/photos/simplesimon/163384848/ (solidstate usb relay switch)
[Discover] Industrial Control - Bulletin 700-HA Tube Base Relay http://www.ab.com/en/epub/catalogs/12768/229240/229266/229643/229691/tab3.html (relay)
[Discover] Relays http://www.bcae1.com/relays.htm (automotive electrical reference electronics)
[Discover] Panasonic 12VDC relay spec sheet http://omicron.octopart.com/Panasonic__CA1-DC12V-N__0.pdf (relay specsheet)