Installing Tiger on a Snow Leopard MacBook

My lab is planning to buy a MacBook that comes with Snow Leopard to test our RCP applications (Eclipse). We would also like to install Tiger to test our applications because many of our users are still on this OS.

Is it possible to install an older version of Mac OS X? Is it possible to install it on a virtual machine (e.g., virtual box) or should we install it on another partition (e.g., external hard drive?).

Did anyone try that before?

Lots of things either just don't work or begin to experience problems if you install an older version of Mac OS X on a machine than the version that it shipped with. Mac OS X's EULA doesn't allow for virtualization(i.e. it is a guest operating system) and installing OS X 10.4 on an external drive would still not work with newer hardware. You may just want to get an older machine, or just test out your applications on 10.6