Barack Obama 48
John McCain 46
Barack Obama has taken a small lead in Missouri after trailing by ten there in PPP's most recent previous poll of the state, conducted in late August.
A big trend between the two polls is increased Democratic unity in the state. Over the summer Obama was winning just 78-15 among voters in his own party. That's now up to 89-7. Obama has also cut down significantly on John McCain's margin with white voters. What was a 56-35 lead for the Republican with that group is now down to 52-42.
As it is in every state the economy appears to be a key factor in Obama's Missouri success. 63% of voters list it as their top concern, and among them he leads 57-38.
Part of what's making this state a tossup after it went for Bush in 2004 is shifts in suburbia. The 2004 exit poll showed the Republican winning 52-48 in the suburbs, but Obama currently has a 55-40 lead there.
Full results here.