There’s the ING Marathon in Miami in January 31st, 2010 and one in Las Vegas DEcember 6th 2009. Chai Lifeline has a large group presence every year. If you sign up and join (and commit to raising abt. $1,500, they fly you down and you spend the weekend in a hotel w them), you have access to training and guidance from a top running coach.
There;s a marathon and 1/2 marathon option. I have lots of friends who’ve done it.
Check out : Teamlifeline.com