Track Polls in (Almost) Real Time
The Washington Post poll is updated by 6:30 PM each day, and the site offers trend charting and other interesting survey information.
The USA TODAY/CNN/Gallup poll is also available online, though not updated as frequently. The site also offers polls taken in "battleground" states.
The Rasmussen Tracking Poll is also online -- though with fewer interactive tools -- and is updated daily at noon.
PollingReport.com tracks a number of prominent national and regional polls, updating them as soon as new numbers are available.