UScreenCapture is a DirectShow filter that, when installed, allows you to stream your Windows desktop to any DirectShow compatible program. This would allow you, for example, to record your desktop for training purposes using any DirectShow compatible software, such as Windows Media Encoder (allowing you to even broadcast your desktop).
You can configure which part of your desktop is captured, as well as the framerate to increase performance/quality. And UScreenCapture also supports dual-monitor setups.
Windows XP/Windows Vista/Windows 7