I have found this site called Looperman it is a very good site if you are looking for some beats or loops and the are all free to use. This site works by users generating material and posting for others to use with their musical works or whatever they are using them for. I particularly because they have quite a large selection and there is a pretty defined search engine to help you find just what you are looking for. They one drawback with sites like these are that you will need to create a free account to enable you to download things. I find that this site is very useful and use it fairly often to create my music.