If you're an American living abroad, don't forget that you are eligible to vote in the primaries as well as the General Election. Of course, in the 2000 general election two states (Florida & New Mexico) were decided by fewer than 1000 votes. Register today.
{By the way, for any US politics junkies, this is a fascinating site. Lots of great maps. My favorite is the breakdown by county. You can see how support for one candidate or the other is geographically spread and how state lines don't determine support, although obviously they do determine the winner.
And information on every election going back to George Washington's.}