Google Scholar, the newest Google product allows free access to full text legal opinions from federal and state courts. Google's site says it carries state cases back to 1950, federal appellate and district court opinions to 1923, and U.S. Supreme Court cases to 1791. It also includes a "How cited" tab, which appears to be a Shepard's type feature that lists other cases and law reviews that mention or quote the case at issue. You can search by case name or legal topic and use regular google search techniques. Also supposedly includes a large number of law reviews and bibliographic information from about 50% of Heinonline's current journals. Apparently, Google Scholar has been around awhile but only added all this legal stuff about two weeks ago. Here's one appellate attorney's blog on his experiences testing google's new service: CrimApp Blog