From CNN:
It all adds up to a seven point advantage for President Barack Obama over the former Massachusetts governor, with 52% of registered voters questioned in the survey saying that they’d vote to re-elect the president and 45% backing Romney.
“Among independent voters, the poll indicates President Obama has a 53%-42% lead,” CNN Polling Director Keating Holland said. “The president holds a nine point advantage among women voters and a smaller six point edge among men.”
As far as I can tell, CNN did not release the demographics of this poll, so I don’t know what the partisan breakdown is.
Twenty-eight percent of Republicans and Republican-leaning independents think Romney should pick Marco Rubio for veep, while Chris Christie and Paul Ryan are tied at 16 percent support. All the other vice-presidential contenders poll in the single digits.