Wilhelm scream

The Wilhelm scream is a movie and television sound effect first used in 1951 for the movie "Distant Drums". The effect became popular again (its use often becoming an in-joke) after it was used in "Star Wars" and many other movies as well as television shows and video games. The scream is often used when someone is shot, falls from a great height, or is thrown from an explosion.
The sound is named for Private Wilhelm, a character in "The Charge at Feather River", a 1953 western in which the character is shot with an arrow. This was believed to be the third movie to use the sound effect. It was the first use of the sound from the Warner Brothers sound library.
History.
The sound effect comes from a series of sound effects made for the 1951 movie "Distant Drums". In a scene from the movie, soldiers are walking through a swamp in the Everglades. One of them is bitten and dragged underwater by an alligator. The scream for that scene was recorded later in one take. The sound was labeled as "man getting bit by an alligator, and he screams." 
Growing popular.
The Wilhelm scream began to become popular when Benjamin Burtt Jr. found the original recording (which he found labeled as "Man being eaten by alligator") and put it into a scene in "". Burtt is credited with naming the scream after Private Wilhelm (after a soldier in "The Charge at Feather River" who was shot by an arrow and screamed). Over the next decade, Burtt began using the effect in other films he worked on. This included most projects with George Lucas or Steven Spielberg. It is used in all of the Indiana Jones movies. Other sound designers picked up on the effect, and use of the sound in movies became a tradition in the community of sound designers.
Research by Burtt shows that actor and singer Sheb Wooley, best known for his song "Flying Purple People Eater" in 1958, is likely to have been the voice actor who first performed the scream. This has been supported by an interview in 2005 with Linda Dotson, Wooley's widow. Burtt discovered records at Warner Brothers from the editor of "Distant Drums". These records include a short list of names of actors scheduled to record lines of dialogue for roles in the movie. Wooley played the uncredited role of Private Jessup in "Distant Drums." He was one of the few actors used for the recording of more vocal parts for the movie. Wooley performed more sound effects, including the screams for a man being bitten by an alligator. Dotson confirmed that it was Wooley's scream that had been in so many westerns, adding, "He always used to joke about how he was so great about screaming and dying in films."
Usage.
The Wilhelm scream has become a cinematic sound cliché. By 2008 it had been used in many works, including over 216 movies, television shows and video games . Some directors, most notably George Lucas, include it in almost every one of their productions. 
In 2010, a Wilhelm Scream App was released on the Apple iPhone. As of 2011, it is still free to download.
The second single by British artist James Blake was called "The Wilhelm Scream" and was released in 2011.