Boot Camp is software included with OS X so you can run compatible versions of Microsoft Windows on an Intel-based Mac. You can run the Windows operating system on your Mac at native speed—without the performance penalty that comes with software emulation or "virtual machines."
Windows applications have full access to multiple processors and multiple cores, accelerated 3D graphics, and high-speed ports and networking such as:
If you're using Mac OS X v10.5 or Mac OS X v10.6, the Boot Camp support software is on the Mac OS X installation DVD. For OS X Lion v10.7 or later Windows drivers are automatically downloaded from Boot Camp Assistant.
Boot Camp: Downloads & Support Software
Setup Guide from Apple: Boot Camp Mac OS X Lion (10.8)
Setup Guide from Apple: Boot Camp Mac OS X Lion (10.7)
Setup Guide from Apple: Boot Camp Mac OS X Snow Leopard (10.6)
Apple Boot Camp Support
Apple Boot Camp Manuals
Referenced from Apple.com