Freesound - The Freesound Project is a collaborative database of Creative Commons licensed sounds.
Whyp - Free & fast audio sharing site
Sample Focus - The easiest way to find the perfect audio sample
Vocaroo - Vocaroo is a quick and easy way to share voice messages over the interwebs.
Moody sampler - A cloud connected audio sampler, including 1000+ instruments
SoundCloud - Enjoy music & follow favourite artists