hi matt,
well i can only give you one url,
www.findsounds.com
is your best bet.
on there you will find several hundred sounds varying from animals to household sounds and even a wide range of weaponry both real and sci-fi and historical.
however if you want to search yourself for different sounds then i suggest you use
http://alltheweb.com
just click on audio and type in your search peramiters into the edit box.
for example if your into video game noises like from super mario or the like you will find several references on alltheweb.com.
however sometimes alltheweb.com does have the habbit of listing websites that cannot be found, or have long since disappeared off the internet.
good luck.
arch
Pay my respects to grace and virtue,
Send my condolences to good,
Hear my regards to soul and romance,
They always did the best they could.