it's not possible to run anything across the two platforms. you'd need to use wine, a free compatability layer (emulator to most people) or commercial optinos like win4lin and vmware. search the net for more infor on them.
you can partition using a bunch of different things. in redhat, it's normally diskdruid, althoguht there's fdisk, cfdisk and a load fo others
you should always install windows first and then linux, but as long as you make a boot disk you can install windows at a later date no problem. as long as you put it in a primary partition of course.