When you are making animation, do you download sound effects (like some hits, scream, breaking glass ...) from the Internet   or   do you make it by yourself ( in front of your computer ?)

I get my sound effects from findsounds.com only some sounds i make on my own. You just have to right click the sound effect you like and save the link

The internet is easier and better quality than anything I'd make, so I stick to that. If you have the right equipment, know how, and need a really custom effect, go ahead and try to do one yourself.

When I was watching "The Lab with Leo" on tv the other day there was mention of a website called SoundSnap (www.soundsnap.com) and its a really great site. It is a collection of original sounds made or recorded by its users. Of course if you can't find exactly what you're looking for sometimes it can be fun to create your own effects. If you can find footage of Ben Burtt on YouTube or elsewhere its really amazing to see how he's created some very memorable sounds still leave some sound people in awe.

P.S. I found a great video featurette for the upcoming movie WALL-E featuring the brilliant sound design of Ben Burtt.

http://www.youtube.com/watch?v=7ZRPHp3UxvA

also for mac users there is sound effects in *GarageBand*