With YouTube, Google video, and other web based video browsers, it's pretty easy to embed video into your blog posts. Once you find the desired video, click on the "Embed" code or "Source" code, copy it, and put it into the body of a posting. It's always a good idea to identify the basic topic of the video, as well as the resource. In fact, you should try to get in the habit of doing that for any material you post that did not come from your own creative brain!
Check out this video - an overview of Web 2.0 from Utechtips, which provides screencasts for educators and videos from students.