Quote by Xbox360Achievements.org:
The comprehensive add-on brings the heritage of the AFL to Madden NFL 10 with all-new 1960’s-style presentation elements. Referees don the orange striped AFL uniforms, official AFL markings and logos decorate the field, and more – all while featuring a retro football card-like user interface and classic film grain broadcast camera.
The eight original AFL teams will be represented by name and wear their historic uniforms, including the Buffalo Bills, Denver Broncos, Kansas City Chiefs (as the Dallas Texans), New England Patriots (as the Boston Patriots), New York Jets (as the Titans of New York), Oakland Raiders, San Diego Chargers and Tennessee Titans (as the Houston Oilers).
The 15 AFL Legacy Game matchups during the 2009 NFL regular season will include the Legacy Pack presentation in the offline Franchise mode, as well as during the Play Now, and Superstar modes. Historic AFL uniforms can be selected in any mode – offline or online!
The AFL Legacy Pack game add-on for Madden NFL 10 will be available on September 24th for 560 Microsoft Points.
Expect new achievements/trophies also.
Now for the new achievements.
Blast From The Past 30G
Win an AFL-themed Madden Moment with AFL presentation turned ON.
Orange Sherbet Anyone? 30G
Win an exhibition game with AFL presentation turned ON. 5 min qtrs, All Pro (no co-op)
AFL Invades Franchise Mode 30G
Win an offline franchise AFL Legacy game with AFL presentation turned ON.
AFL Goes Online 30G
Play online wearing AFL jerseys. 5 min qtrs, All Pro (no co-op).
Secret Achievement 30G
Continue playing to unlock this secret achievement.
I personally haven't bought the new madden but I will definitely be picking it up in the near future. I also think the pricing isn't too bad for all the content you get considering most games charge 800MS for expansions and add-ons.