These comments are all great. For video marketing, you can use third-parties to help create professional quality video (like http://silverdock.com/). You can also get started with homemade videos -- the Flip camera and Creative Vado cameras do a decent job, for video marketing that doesn't need to be professional quality. As a previous poster pointed out, YouTube is becoming a major search channel and so it's a great way to promote.
I'm pretty negative on podcasting, I think the cost/benefit isn't there and the mass audiences are not there (for most promotional purposes). If your business is based on entertainment / educational content to begin with and a podcast fits your content type, then it may be more useful.