Next time you're watching your favorite movie, close your eyes and listen to the sound effects. Everything from footsteps to machines to ambient crowd noise is a sound effect.

They were either recorded during shooting or added in post-production. You'd be surprised how integral good sound effects are to movies.

You should give them a try in your own movies or slide shows. You can find thousands of free ones at AudioMicro.

Make sure you read the terms of use before including them in a public video. The free sound effects available for download are for your personal use and enjoyment only.

Cost: Free

Link: www.audiomicro.com

System: Windows XP, Vista, 7, Mac OS X