The Slingbox is a simple device that plugs into any TV source and allows you to watch the source from many Windows machine that is connected to the Internet. It also allows you to control the TV source via a virtual 0n-screen remote control. That means you can hook it to your TiVo at home and watch live or pre-recorded television from a different room in your house, outside (via WiFi), or from a hotel room while traveling. All you need is a high-speed net connection at home and at the location you want to watch TV from.
I’ll be purchasing the $249 device as soon as I get back from teaching a class at the Lepp Institute in California.