Undead or Alive: A Zombedy (2007)

Army deserter Elmer Winslow and local cowboy Luke Budd are on the run after robbing the evil Sheriff Claypool, stealing his money and fleeing the town, they find themselves with an angry posse on their trail. Joining Elmer and Luke is an Apache warrior, who's out to wreak vengeance on behalf of her decimated people; her plan is to attack the U.S. Army wherever she can find it, and she takes Elmer up on his offer to go with her to the nearest Army outpost he knows. Their plans become complicated when they discover that, as a result of the great Apache Geronimo's curse on the white man, all the people of the surrounding areas have turned into zombies.