Raymour & Flanigan has rather handy, easy to use, and not to mention FREE, room planner on their website. You pick the dimensions of your room’s size and then start plopping down furniture, rugs, and accessories inside it. When you’ve settled on a favorite, you can print your design, or, if you sign up as a registered user, you can e-mail your layout to friends and family for input or save the design for future reference.
When furnishing your virtual room, I’d suggest using the “Generic” templates, not the “Our Products” as the former is a bit easier to use and has plenty to choose from including structural elements such as windows and fireplaces and, to really make it feel like home, a cat and dog!