This site has a great idea - track the state by state voting polls and then assign electoral votes based on that to see if McCain or Obama has the edge in the National Election.
Unfortunately the methodology has a serious flaw until the Demcratic primary is over, and that is the fact that Clinton supporters are likely to shift their perceptions dramatically once Obama is the "annointed" candidate. My view is that almost all of Clinton's support will flow to Obama even though at this time there are many Clinton supporters saying they won't vote at all or will even support McCain.
My view is supported by the 15 day average which shows Obama winning general election while the 50 day average favored McCain. By next week, when the Democratic Primaries are wrapped up and Obama will be the presumptive adn perhaps the actual winner, I think the electoral voting will line up with national polling and show Obama with a strong lead over McCain.