The best astrology sites I've found which will give you a free natal chart interpretation as well as free astrology forecasts and compatibility interpretations are listed below.
Astrodienst is the best online resource for a vast amount of quality free information. Get started by inputting your birth data (date, time, location) here. After inputting your data, you will be linked to a customized report based on your birth data. The page will tell you where your Ascendant and key planets are placed and will give you an interpretation of what this means. At the bottom of the page you will find your natal chart data. To continue from there with more free information (chart drawings, forecasts, compatibility reports, etc), scroll back up to the top of the page and click where it says "Free Horoscopes".
Astrology3D is second only to Astrodienst as a great site for free natal chart interpretations and free astrology forecasts. Get started by inputting your birth data here. After you've input your birth data and are transferred to the second screen, you will be asked if this report is for you or for someone else. Say "someone else", or you might get an error report with the free version.
Chaos Astrology is another great site for high-quality free natal chart interpretations. Check out your free birth chart here.
If you are interested in free astrology software (as opposed to chart interpretations) check out the section on the best astrology software here at Aquarian Digest.