Jayson Stark previews what the 2013 schedule might look like in his new Rumblings & Grumblings column today:
20 interleague games
76 division games (19 versus each opponent)
66 intradivision games
Finally, each team in a division will play all of the same opponents, except for four interleague "rivalry" games. The only glitch is that teams won't play exactly the same number of games against each opponent. (A club in the AL Central, for instance, would play three games apiece against four NL East teams, and four games against a fifth.) But that was the only way to make the rest of the schedule pieces fit together.
So that means the Astros will be playing 20 interleague games (which will be awesome if the Cardinals are the Astros "rivals," seeing as how Houston was just moved to the AL West to take advantage of the new "rivalry" with the "Rangers"), 19 games vs. the A's, Angels, Mariners, and Rangers. This leaves 66 games with the other ten AL teams.