TVUPlayer is the best P2P video player out there in my opinion but you're only enjoying half of what it has to offer if you're only watching it.
TVUBroadcast is the tool you'll need to start broadcasting your own video channel and reach millions of users worldwide. It doesn't actually work as a separate application - rather it opens in a tab in your browser allowing you to administer a broadcasting account. Note that it only works properly in Internet Explorer at the moment - uploading files to broadcast using Firefox for example results in a "no WMV file exists" error.
You'll need to sign-up for a TVUBroadcast account first which is quick and painless and once you've opened TVUBroadcast, you can choose to broadcast either by capturing a device attached to your computer (such as a webcam), capture streaming footage over the internet as mentioned, upload your own pre-prepared video file. Unfortunately, you can only upload WMV files at the moment and the bitrate should be below 500Mbps for best streaming.
Once you've chosen, simply select your bandwidth and click "Start" to go live! You can see in the status bar your signal strength (the more the better) and how many people are viewing you at any one time. If you've uploaded a file for people to view, it will simply play on a loop when it reaches the end.
TVUBroadcast is an example of P2P broadcasting at its best democratizing the airwaves for anyone. The only drawbacks are the lack of Firefox support and lack of support for video formats other than WMV.