Wilhelm is an addon that plays the "Wilhelm Scream" sound when you score a killing blow against another player.
There is no configuration.
The Wilhelm Scream is a sound recorded for a movie in 1951. It was re-used in Star Wars and has made a cameo in dozens of movies since. For more information about the Wilhelm Scream, see the Wikipedia entry. The sound file used is from archive.org "open sounds."
Enjoy
Version History
1.1.1 - Fixed a bug where Wilhelm would scream if you killed a player's totem
1.1.0 - Updated TOC for wow 4.2, also used new simpler combat log filtering
1.0.2 - Updated TOC for wow 4.0+
1.0.1 - Updated TOC for wow version 3.3
1.0.0 - Initial Release