There are plenty of astronomical reference tools and software online that you can download absolutely free. But, the absolute best that I have used so far is an increasingly popular freeware called, Stellarium. Stellarium features realistic renderings of the night sky, real-time celestial motion, a catalog with 600,000 stars, and plenty of deep-sky objects. It's perfect for when you want to observe, but it's too freaking cold to go outside.
So why not take Stellarium for a spin? It's fun, educational, and doesn't cost a penny. You can download it here.