This tutorial will explain the steps to exporting to a Web Streaming file.
1)Once you are done editing your footage in iMovie you can click on File > Export.

2) Now an export screen will pop up, click on the QuickTime icon across the top and then move down to the "Compress Movie For" drop down arrow. Here you will choose Web Streaming.

3) Next you can click the share button at the bottom and you will be prompted with a save screen, choose where to save your file and Type in a name. Now you can save it and upload it to the web.

Keep in mind that the Penn State streaming server has a restriction of 1 gigabyte per file. If your file is larger, try splitting it into smaller separate files or manually adjusting the settings and lowering the quality.