Virtex DeviceSimulator

Hi. I'm a newbie to fpga design and I'd like to know whether it's
possible to simulate the behaviour of a bitstream generated with
ISEWebPack without implementing it on board. Can I use for this the
Virtex DeviceSimulator? Where can I download it? And i'd also like to
test on my computer a vhdl program that writes some stuff to screen. Is
it possible? Thanks a lot.