FAQs, Science & General Paleo Info:
The Paleo Diet - Loren Cordain The guy who pretty much started the Paleo lifestyle
Robb Wolf Can answer some more hard to answer questions and is pretty funny
Marks Daily Apple - Mark Sisson Lots of great articles and FAQs on specific topics
Whole 9 These guys run regular challenges and are great for trying to adapt Paleo as a lifestyle.
Food and Recipe Guides:
Feel free to post any other resources you use in the comments...