Many of you may already know about this, but I just found out about it. At www.gpsvisualizer.com there is a free tool to calculate distances between 2 addresses. From the home page, click on calculators at the top. About the middle of the page, there is a "calculate distance between addresses". Just put your addresses in and it will calculate the direct distance in miles and kilometers.
I work in mostly rural areas, so I am always having to search out longer distances for comps. My MLS has a feature where I can calculate distances between addresses, but it is driving distances instead of a straight line distance.
The website looks like it does all sorts of great things and it is free! You can make a contribution via Paypal but right now, it is all a free service.