GParted -- LiveCD

This is one of the best partitioning tools on the market and is free and easy to use. You burn the program to disc (live CD) and boot to it and it will repartition your harddrive so as to make room for the other operating systems.

I find that using a great boot manager instead of the ones that comes with windows makes it so much easier to install other bootable operating system as this way dowsn't cause MBR issues between operating systems.

I use bootIt NG from terabyte unlimited which is a partitioning tool and boot manager but it costs to use it....
This is a free boot manager that will also serve the purpose of allowing other bootable operating systems

Download GAG 4.9 - free boot manager. Allows boot of up to 9 different operating systems - Softpedia

Together this makes a different approach to dual booting any other operating systems.