Want to install mac on my toshiba g40 vista

I dont want to wipe my hdd and I dont have a spare hard drive. Is there any possible way I can install mac leopard on my laptop and still switch back to vista If I choose to do so without removing any of my apps or files.

Im not very educated in this but i heard something about easybcd, but i still need instructions of it is possible.

 

Here you go http://dailyapps.net/2007/12/hack-attack-install-leopard-on-your-pc-in-just-one-step/