Edit Your Videos Online With Muveemix
I've been messing around with a web application called Muveemix which lets you mix your videos online. Muveemix allows you to add music, text, styles, title and credits to your videos. It allows you to edit videos that are up to 100MB in size. Its free to use, you don't have to install anything (other than flash) and works pretty well. Check it out!