What are th two Secret Achievements in madden 11 for the xbox 360?

Madden NFL 11 for Xbox 360 doesn't have any "Secret Achievements" per se. The game has 50 Achievements, all of which are listed publicly on the Xbox.com website and in-game.

Perhaps you are thinking of a different game or platform? If you can provide more details about the achievements you're looking for, I can help you find them!