I was looking all over the place for something like this, and was about to install 100MB worth of programs when I suddenly stumble across this!!
http://sites.google.com/site/usonic/SFX ... ects=0&d=1
(uploaded to my google sites, but just to make it clear again, I did not make this program.)
It generates simple sound effects. Hope this helps someone as it helped me. This is perfect for pixel-art games.
Made by DrPetter, wherever you are now, thanks!