538
I tend to get my poll information for the presidential and senatorial races on fivethirtyeight.com. The prediction methodology is verra, verra good (it uses weighted polls measured against past performance).
I often just poke my head in to see some of the numbers (win percentages for both candidates, landslide percentages for my candidate, the 60-seat percentage for the senate, and the numbers for a few key states). The stories, however, are interesting, too.
You can get the stories as a LiveJournal feed. Add 538dotcom_feed to your friends list.