There's a trick to this that I learned...
First, using the Windows installation CD, partition your drive with however many partitions you plan on using for your Windows and your Linux distros. You only need to format the Windows partition at this time.
Next, install the Windows OS on the system first
. Windows has a Darwinian need to seek out and eliminate other operating systems on the same system
, or so it seems sometimes. Once Windows is in and running on the partition you want it on, move on to the next step.
Install your favorite Linux distros on the already created partitions on the drive, saving your primary distro (preferably a Debian-based one) for the last step below. Format the partitions using the install disks as ext3, ReiserFS, or whatever. Remember, you only need one
/swap partition for all
your Linux distros. Do NOT
install a bootloader with any distros but the last one you install (see below).
Lastly, after installing all but the last Linux distro, now you can proceed to install this last one. Allow the bootloader to be installed on this one. If it's a Debian-based distro... Mepis, Knoppix, Ubuntu, etc., its GRUB will automagically pickup and correctly configure all the OS's on your system, Windows included. This will now become your primary system bootloader.
This is the easiest way I found to do this on a fresh drive. There are other methods, though. That's the beauty of computers, and GNU/LInux in particular... you have options.
Best of luck!
PS: You can, of course, partition with gparted or some other Linux partition app, but since you have the Windows disk in first, may as well do it with that partition app.
PPS: Don't forget any Fat32 common storage partitions for all the OS's on the system, if you need one. Set it up in the first step above also.