using different desktops

Well then your only other easy options are VirtualBox or some form of remote Workstation/Trojan.
VirtualPC is good for running Linux inside windows.
VirtualBox is good for running windows inside Linux.
VMware is good if your willing to spend a load of time tweaking it for best performance, personally I don't use it anymore.
VirtualBox is a better solution for Linux systems and its easier to run.
I also heard a rumour about someone taking a Mac version of Virtual PC and running it on Linux but I never bothered looking into it.
(I imagine it would be buggy as sh1t.)
Your call.