JahShaka - An open source video editing software that is currently in Alpha stage but has features found only in expensive video editing software suites.

Works on Mac, Linux and Windows. The interface might take some time for you to get started otherwise the software is definitely the most powerful one out there. And the price is just right. $0. Also does 3D effects which you won't find in other free video editors.

Here is the link to download it . JahShaka