Want to broadcast live coverage of the chaos at your local Apple store? How about a live demo of your new iPhone accessory? Or your presentation at a business seminar? Whatever images you want to share with the world, all you need is an Internet-connected notebook, a Webcam, and Ustream.tv.
The service lets you set up scheduled events, send out invitations, embed video in your site, and archive your broadcasts for later Web-based viewing (YouTube-style). As for equipment, you can use either a Webcam or a camcorder that has Webcam features; just make sure to bring along a microphone if your camera doesn't have one built in. If you're broadcasting from somewhere that lacks Wi-Fi, you'll need a cellular modem card or tethered cell phone (preferably something of the 3G variety, as video quality can really suffer if you don't have a fast connection).
I really dig this service, and not just because it's free. With minimal gear and a decent Internet connection, you've got the tools you need for a fully functional mobile TV studio.