Most of the sound files contained here, can be found at:
www.soundbible.com
and are licenced under:

Creative Commons - Attribution 3.0 
Creative Commons - Attribution-NonCommercial 3.0
Creative Commons - Sampling Plus 1.0


Overview:

BikeHorn - Sampling Plus 1.0 - StickInTheMud 
CatMeow2 - Attribution 3.0 - Mr Smith
KittenMeow - Attribution 3.0 - Mike Koenig
Applause - Attribution 3.0 - Mike Koenig
AirHorn - Attribution 3.0 - Mike Koenig
RingingPhone - Attribution 3.0 - Mike Koenig