The whole windows on mac- help!

OS X won't run on FAT or NTFS and Windows won't run on HFS+ so you have to partition. Bootcamp makes partitioning into, basically, a one click process.

Once it's partitioned and you have your driver CD, just boot the computer from the Windows CD and install as normal.

RAM allocation is only for Parallels and when Parallels is closed OS X can access all the RAM again.

you can use both if you want. parallels allows you to use your bootcamp Windows partition as the virtual OS that launches within OS X. That way you don't have to have 2 installs of windows taking up your hard drive space. vmware is another option with similar features. the beta is free now and u can pre-purchase the final release for about 1/2 price right now. both Parallels and VMware sell for $79.99 at full price.

Parallels and VMware are great for using windows apps from within OS X and is ideal for basic computing needs (-i.e.- anything 2D). both Parallels and VMware have developed support for 3D acceleration so you can get that as well for games, CAD-like work, and whatnot, but you're inevitably going to take a performance hit since your system resources are being split between the operating systems.

the most recent beta of VMware actually allows you to launch windows apps w/o having to launch into the whole windows scenario. Parallels also allows for this per, "Run Windows programs like native Mac applications with Parallels Coherence"

bootcamp is free and gives Windows complete access to all of your system's resources since it is booting into the OS, but doesn't allow for use of windows or windows apps (virtualization) from within OS X.

If you want to game do BootCamp and then use Parallels for those times when you need to use the odd Windows programme.