Sara's ear shattering scream gets very old, very quickly. This is just two blank .wav files that tell WoW to play nothing, instead of causing you to become temporarily deafened every time Sara screeches.
These two yells in Ulduar are silenced:
1. Loud Scream. Help me! Please get them off me!
2. What do you want from me? Leave me alone!
The ghostly screams in Naxxramas are also silenced:
2. Please stop!
3. Help me! Save me!
4. Please no!
Extract the files, NOT into your Addons folder, but into your /World of Warcraft/Data/ folder.
Just delete the newly created Sound folder and it's subdirectories in your /World of Warcraft/Data/ folder.
v3 - just noting that this does still work in the latest patch