Download the Comet Filter from here. (http://www.borisfx.com/login/reg_form.php?action=Comet)

Fresh from my inbox ....

For a limited time, we are offering a free, fully-licensed plug-in from Boris Continuum Complete 6 - BCC Comet, an auto-animating filter based on Boris Continuum Complete's Particle System filter. BCC Comet can be used to create streaking comets that move in 3D space. The free BCC Comet filter is available for Adobe After Effects, Adobe Premiere Pro, Apple Final Cut Pro, Apple Motion, and Apple Final Cut Express.

There is also a tutorial (http://borisfx.cachefly.net/borisfx/tv/comet.html) to go with it too.

Andrew