I do not know them all but I know the Chi. bears, N.Y. giants, Cin. Bengals, Chi. cardinals, Phi. Eagles, Pit. steelers, and GB packers are what i can think of. There are two teams that played in the first season of the NFL (1920) that exist in 2008. They are the Decatur Staleys, now known as the Chicago Bears and the Chicago Cardinals, now known as the Arizona Cardinals. The Green Bay Packers entered the NFL in 1921.
It was the 1972 Miami Dolphins.
The Broncos This Year HaHa
1920
In 1995 the bear owner started a new team and they name it Ravens and move to Baltimore
dallas cowboys
It was founded for the American Football League, but the NFL made a stronger offer for the team, so the team waited until 1961 and became an NFL team.
The Chicago Bears (George S. Halas)
The Dallas Cowboys were an NFL expansion team in 1960.
The Vikings joined the NFL as an expansion team in 1961.
The Cowboys joined the NFL as an expansion team in 1960.
The team that wins the super bowl that year.
In the 2010 NFL Draft, that is the Washington Redskins.