Is it possible to install Mac os x in virtual machine on a macbook pro? I'm going to try diffrent versions of MacOSX on my macbook pro. I have a Snow Leopard installed there, and need something else (possibly a Tiger) as second solution, to test the software. 

So I thought of a virtual machine that would be running on my Snow Leo and have a Tiger running on it. 

I tried VirtualBox, and install a MacOsX from there (from a .iso disk image), but it basically hangs during the very beginning of the instalation. 

Is there any good and easy to perform solution to do this?
The only version of Mac OS X that can be legally virtualised is Mac OS X Server:

http://www.virtualbox.org/manual/ch03.html#intro-macosxguests