Sure, you can dual boot both OS'es. Linux works fine along side Windows, but before getting yourself into troubles, make backup of your stuff first. SuSE has a great installer, easy to follow. You will need to resize/create partitions for your HD in order to install Linux, but it should not be a problem at all.
Another alternative is to use Live CD's. They are bootable and run enterely from the CD without installing a single line to your HD. It's good only as a rescue disk, see how Linux looks like and if your hardware is Linux-friendly. Other then that, HD install is the way to go. SuSE offers a Live CD, there're many others, as Slackware, Knoppix, Ubuntu...