check out www.insuremytrip.com
Fill in the required information and they will provide you with quotes from many companies. Pick the plan/amount of coverage that most matches your needs and budget.
Renee - The better half of RobRen :-)
Carnival - Spirit: Alaska (August 8, 2007)
Carnival - Miracle: Exotic Western Caribbean (April 9, 2006)
Royal Caribbean - Explorer of the Seas: Eastern Caribbean (January 2005)