I'd like to be able to use my current system (Tiger, OS 10.4.11) and Snow Leopard at the same time. I would like to compare them before I commit to one or the other.

I just ordered Snow Leopard (OS 10.6.3) from Apple and have the install disc. I never partitioned a drive before or used two OSes at once.

How do I install Snow Leopard so that I can use it along with Tiger rather than replace Tiger on the same hard drive on my imac?

I have a backup drive with a OS 10.4.11 clone.