http://www.soundjay.com/
Few gigs of high quality sound efffects for free, terms of use as followed:
"Sound Effects
You are allowed to use the sounds free of charge and royalty free in your projects (such as films, videos, games, presentations, animations, stage plays, radio plays, audio books, apps) be it for commercial or non-commercial purposes."
http://www.soundmorph.com/index.php?page=free
"All CONTENT in this product is licensed, but not sold, to you by SoundMorph. for commercial and non-commercial use in music, sound-effect, audio/video post-production, performance, broadcast or similar finished content-creation and production use."
http://www.blastwavefx.com/Free-SFX-Download-Pack-%231/t3/articles.html
"You have the right to synchronize the audio content from any Blastwave FX royalty free product with audio and/or visual productions or applications such as: film & video productions - training and marketing presentations - corporate videos - on hold messages - radio presentations or commercials - television presentations or commercials - musical recordings - live performances - Web pages - multimedia presentations - interactive programs - computer games - audio-visual or computer generated displays, programs or presentations which may incorporate streaming audio or podcasts (hereinafter referred to as "the Production")."