Sakari-Infinity is a website that allows you to download free music, as long as you don't alter or sell it etc. It's a great site if your looking for background music.
All Audio Files provided by Sakari Infinity are licensed under a Creative Commons.
This user on youtube has a great library of sound effects! To obtain a particular sound effect, go on its video, copy the url, then go on http://www.youtube-mp3.org/ and paste the url there, and download the MP3 version that you can then edit in Audacity and put into your game!
Scratch is developed by the Lifelong Kindergarten Group at the MIT Media Lab, with financial support from the National Science Foundation, Microsoft, Intel Foundation, MacArthur Foundation, Google, Iomega and MIT Media Lab research consortia.
Scratch is a programming language that makes it easy to create your own interactive stories, animations, games, music, and art -- and share your creations on the web.
Hey people! I just want you all to know if you are looking for sound effects to add to your game, go to this URL: http://themushroomkingdom.net/wav.shtml. It offers lots of old school sound effects, mainly Mario ones. Anyways, hope i helped you out!