The aep is a project file, not a video. It's what you open in After Effects. You need to open the .aep file and then render a video which you can then upload. Since this is for the web, you'll probably want to export it as a .flv file (flash video), because a .avi is generally a large file. Go to file -->export and I believe you can select flv or flash video there. I don't know how you're website is managed, whether you have a content management system that lets you simply upload a video to be automatically embedded. If you can't do that, you'll have to do a little coding, but hopefully you know how to do that. Good luck.