Jaycut http://jaycut.com/ was a free online video-editing tool which let you upload your own video clips, photographs and audio and create your own film. At the moment Jaycut is not available. Alternatives are below:
WeVideois an online free video editing tool which can be used by multiple users collaboratively – there are options to pay for additional features.
FileLab is an alternative to Jaycut which lets Microsoft Windows users upload video or audio to this online tools where video or audio can be edited
Ten Ways to create Videos without installing software is a post by Richard Byrne which describes ten tools which you can use to create videos online without the need for installation of software.
Pixorial is a free online tool for uploading video and undertaking basic video editing, trimming and adding music. There are also premium options, including for more storage.