WirecastTurn your computer into a TV studio

Full scale video production studio for your desktop or laptop computer
Capture live video from multiple cameras & control switching between cameras
Import pre-recorded video, audio, graphics and slides
Picture in picture enables viewers to see multiple sources, including the presenter/host
Chroma key, 3D graphics & transitions enable creation of professional quality webcasts
Stream live and/or record to disk for on-demand viewing
Encode to popular streaming formats (Flash, Windows Media & QuickTime)
Simultaneous encoding to multiple bit rates for a variety of quality choices

Link for more information: http://www.telestream.net/wire-cast/overview.htm