NASA has released tons of audio files from their digital archives. These are sound bites from the launches and famous incidents from the various flights over the years.
They have also updated their official app for the Google Android platform which incorporates this feature.
The newly updated app offers:
Fixed issue with auto-wallpaper service erroneously setting wallpaper
Added Ringtones feature (from main menu button)
Added background service for automatically setting your wallpaper to the newest NASA Image of the Day or Astronomy Picture of the Day on a daily basis (go to settings from the main menu to enable service)
Higher-Res image thumbnails (some devices)
Added ability on newer devices to play embedded videos in News and Features articles
Fixes for GPS issues