All the stats ever: http://www.baseball-reference.com/
Minor league stats: http://www.baseball-reference.com/minors/
Winter League Stats: http://mlb.mlb.com/milb/stats/
Daily Baseball News Sites
Strat-O-Matic Buy the game and the card rating guide.
Lammana's Baseball Bulletin The John Lammana webpage. Maker of the Lammana card guide and Draft guide as well as the Lammana Strat preview guides.
Strat Fan Forums Cuss and disscuss all things Strat related.