Watch out for many of those sites Thug posted, they are biased towards right wing radical views. The more moderate republican views can be seen on the
Washington Post and
The American Spectator.
As for more liberal views, you can check out
The New York Times or
Huffington Post (pretty left wing radical also).
My favorite place for learning about politics is on here:
Reddit Political Discussion or on the
main politics hub which has links to the many other political subreddits such as libertarian, green party, Occupy Wall Street factions, Republican and Democrat factions.