I've been reading a lot of John Berardi's stuff (Gourmet Nutrition, Precision Nutrition, No Nonsense Nutrition, and Grappler's Guide to Sports Nutrition). So far I've increased my calorie intake by about 500 calories/day and I've lose 15lbs of fat and gained 5lbs of muscle.

I am going to take a look into p90x. I don't think I will follow their nutrition guide (since I am having so much success already) but the workout routine could lead to huge gains. I'll let you guys know.