Boot camp is built into Mac OS 10 (Leopard) and is free. If you're not on Leopard then you can download it from here
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Bootcamp is the software that allows you to install Windows, you'll still need a copy of Windows with a license *ahem*
The Drivers are provided by Apple as it's there equipment and allow you to work on XP, Home, Professional SP2 (or later) and Vista.
Here is a FAQ for boot camp
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and the Installation and Manual
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