i installed windows 7 successfully. When I installed it, I created 40 gb of unallocated space in the hard disk for the Fedora installation. However, whenever i start the partition editor during the Fedora installation, it says that there is no free space in your hardware, even though it shows 40gb space in the disk partition table.
why not try first using a Virtual Machine to play around with fedora, instead of partitioning your HD. VirtualBox is free and open source. You can download it from http://www.virtualbox.org/
using a VM is the simplest way to get an installation of linux which co-live with windows. Also, you can select a folder which you can share files between windows and your virtualized linux.
Here is a guide to installing fedora as a dual boot with windows 7. (even though is says fedora 11 it will works for 12 and 13 as well. Give that a shot and see what you can do.