Marvel Studios has brought aboard Rich Wilkes (the "XXX" film series) to write the screenplay, which will adapt the story of Danny Rand, the Marvel martial arts superhero created in the 1970’s.
In the Marvel Universe, Rand is the son of a wealthy explorer who trains in the mystical arts and eventually gains the power of the legendary Iron Fist, a magical fighting power that gives him indestructible fists. First using the power after his father’s death, Rand continued to bear the mantle in the fight against evil. Later, Iron Fist popularly teamed with Luke Cage (Power Man), who allegedly has his own film in development.
In the current comic book continuity, Iron Fist is member of the New Avengers, a team that includes Cage, Jessica Jones, Spider-Man, Wolverine, Ms. Marvel, Hawkeye, Mockingbird and The Thing (of the Fantastic Four). Studio rights preclude several of those characters from appearing on the big screen together for the time being, but a Power Man and Iron Fist crossover is certainly possible.