I highly recommend checkin

I highly recommend checking out the Freesound Project (“a collaborative database of Creative Commons licensed sounds.”):

http://freesound.iua.upf.edu/

For those with an interest in creating and sharing sounds, I would also recommend signing up and contributing audio files for others to use. I’ve done this and it’s quite interesting to see how my sounds end up being used (or just to read the comments, such as for the snoring sample I uploaded).