http://www.findsounds.com/types.html
http://freesound.iua.upf.edu/searchText.php
http://www.stonewashed.net/sfx.html
http://www.grsites.com/sounds/
http://www.koumis.com/soundfx.htm
http://www.partnersinrhyme.com/pir/PIRsfx.shtml
http://www.f7sound.com/snd.htm
http://www.pacdv.com/sounds/
Freesound is indeed the best of those so far.
http://freesound.iua.upf.edu/
More than 350000 sounds and growing
All of them under a Creative Commons license, so no worries about copyright as long as you attribute the author
You can use the sounds in commercial and non commercial products *
Indeed the best search engine, imo
A big community of more than 400000 users and growing at a rate of 800 per day
more than 2 million downloads
All this in 2 years of existence
So, when you read one of those “largest sound database of the web”, well… you know… link them to Freesound
http://freesound.iua.upf.edu/
*(except for advertising of a product that is not made with those sounds
i.e.
-is ok to use a sound in an ad for a music album that contains songs where this sound is used, or a game, or a website, or a podcast, or a movie etc…
-but not ok to use a sound in an ad for McDonalds or any commercial product wich does not contains the sound in it )
Free Sound Effects and Loops has completely free sound effects at http://www.freesoundeffectsandloops.com
http://www.freesoundeffectsandloops.com has totally free .wav file sound effects and music loops to download and http://www.sfxsource.com has royalty free sound effects and production music