At this hour, the Intrade futures market has the Democratic race at practically a dead heat. Clinton has a slight edge, with a 50.5 percent probability of winning the Democratic nomination, while Obama trails at 48.1 percent. As reflected in the polls, Obama has been getting closer in recent days. On the Republican side, John McCain has it all but locked up, with traders giving him more than an 89 percent chance of winning the nomination. So what exactly is Intrade? Itís a way to buy and sell contracts Ė betting, really - tied to not just the election, but most anything going on in the world. And the numbers tend to be pretty reliable (they called every Senate race in 2006 and every state in the 2004 presidential election). Of course, they were totally off in New Hampshire, but then again, everybody was.