VirtualForge has created this neat video illustrating XSS (Cross-Site Scripting). It uses a cartoon which walks you through the process, start to finish, illustrating each step. In doing so it provides the clearest definition of XSS I’ve seen.
You can find quite a few videos about XSS on YouTube, but I can’t show many of them in class due to length or other reasons. Many of them have long periods where you’re looking at a screenshot while the faceless narrator gives background information. I would still like to find, however, a clear and concise (about 5:00) video that would be usable in class where someone actually demonstrates a XSS exploit. Until I do, use the VirtualForge video to get a clear idea of what XSS is, then maybe use the YouTube videos linked above to dig deeper and see what it looks like in action.