Whether you need basic tools that let you easily cut-off desired scenes, add background music, integrate animations, etc. or something more powerful, it’s all here. While each service offers different editing features, functionality is the same everywhere, i.e. (1) upload your video either from your PC or grab it directly from the web (i.e Youtube, Metacafe etc…), (2) edit/mix/enhance it, and (3) share it with others.
Something I ran across that might be of use.