OSNews posted a good article on how to build your own Hackintosh. They provide a complete list of hardware and a step by step how to on getting it up and running.
The most well-known way of setting up a Hackintosh is to download a hacked Mac OS X Leopard image, burn it to a disk, and go from there. This method, while easy, has several disadvantages. First of all, if you’re in the United States, or another country with DMCA-like laws, this hacking can actually be against the law, and as such, it might not be a wise thing to do. Secondly, using such hacked Mac OS X images means that updates from Apple, such as the latest Leopard 10.5.7 update, will definitely ruin your system.
Check out the guide and build your own Hackintosh.