Iowa Polls

Is there anyway we can setup which Iowa polls are which? Which ones are official and which ones are paid for or whatever? I see threads here all the time about how "Ron Paul won today's Iowa straw poll." Then in the same day, I'll hear on the radio that Newt is leading by a landslide in Iowa. Is there a site that organizes these polls so it's easy to tell which ones are more legit? Or can someone explain?
Thanks.