iJET Travel Intelligence - http://www.ijet.com Commercial organisation providing detailed travel advice and warnings for various destinations.
Air Security International's Hot Spots - http://www.airsecurity.com/hotspots/HotSpots.asp#Amer Detailed listing of security related news items from around the world updated daily.
UK Foreign & Commonwealth Office: Travel Advice by Country - http://www.fco.gov.uk/servlet/Front?pagename=OpenMarket/Xcelerate/ShowPage&c=Page&cid=1007029390590 British government official travel advice and warnings for all countries.
Fielding's DangerFinder - http://www.comebackalive.com/df/dplaces.htm A somewhat 'gung ho' approach to dangerous places but contains detailed information about how to keep safe in some of the world's most dangerous places. Also has a traveller's bulletin board.
Sign in Safe - http://www.signinsafe.com/ Offers the latest travel safety news, along with tools to monitor the safety of people as they travel.
expatexchange.com - http://www.expatexchange.net/expat/index.cfm?pr=newslettercen Registration for email newsletters containing critical travel warnings designed for US expatriates.
Red 24 - http://www.red24.info/nonmembers/ Security service with threat level analysis for business and personal travel itineraries.
Travel Safety Information - http://www.mft.govt.nz/travel/ Official travel advice and warnings from the New Zealand government.