Undead or Alive: A Zombedy(2007)

Guns don't kill people. Zombies kill people.

Elmer Winslow is a soldier on the run from the Union Army, and Luke Budd is a cowboy with a broken heart. When the two misfits rob the corrupt sheriff of an old west town, they have no idea that a plague of zombies is sweeping the country, or that Geronimo's sexy niece may be their only hope of survival.