This "How To" is from Vodstock, a great Vodcast directory.
A vodcast itself is not a video - it is a glorified list of links to videos that is formatted so it can be read by special software. Such software is called an RSS reader and vodcasts are types of RSS feeds. Apple's popular iTunes (version 4.9 and above) can accept vodcasts and FireANT is a good dedicated vodcast reader.
A rough analogy with television would be:
Vodcast or vlog: A television channel
Video file: An individual program
Viewing software: Television set
Vodstock and other vodcast/vlog directories: Television guide
You: The program scheduler and audience
The advantage over television is that you can watch whichever video you like whenever you want. You can also subscribe to as many vodcasts as you like. At the moment, subscribing to vodcasts is free and simply involves registering the address of the vodcast in your software. You don't need to give your name, email or other details to subscribe. Most current vodcasts are personal creations by individuals but over time professional broadcasting and media organisations are sure to enter the scene.
You can now also subscribe to vodcasts on portable media players such as the video iPod. This really is the age when you can watch what you want, when you want, where you want. As Vodcast.nl puts it, this is Couch Potato Heaven!
It's all about convergance. My TV and PC are pretty much the same thing. So I can watch a mix of Vodcast, Broadcast and Streamed media all from the same screen.