Possible Duplicate:
I can't beat Terran as Zerg when they do MMM with a splash of tanks, any ideas?
What's the best combination of units as Zerg against MMM + Siege tanks behind them?
With banelings u won't get close enough to do damage and pretty much any other massed unit (roaches/hydras/mutas) won't do enough damage considering the medivacs and siege tanks.
Any suggestion appreciated!