I use video a lot for creating marketing content, mostly because I hate to type and I think and speak a lot faster than I can type. So for video I do marketing webinars, a great marketing video podcast, this smaller marketing podcast and lots of other marketing video through and with the team at HubSpot.
To be honest, for most people the first steps are easy. I do all these "Marketing with Mike" videos just using a webcam and a PC and edit with either Windows Movie Maker (free!) or Camtasia (expensive). You can use Quicktime Pro ($30) to convert the video formats if you need to, because Windows Movie Maker does not do a good job of supporting the iTunes formats.
What is much more important than the equipment is the content. For all these videos, I have notes to guide me, and I try to take topics from videos that come directly from people I have met in person or online, so I know the videos will be on topics interesting to all of you (hopefully).
Remember, think content before production value.