The University of Southern California’s law library has a nice little listing of law reviews that are available online. The index provides the name of the review (with an active link), a brief summary discussing its subject matter, and a code notation explaining what information is available. These notations include F for full-text, A for abstracts, T for table of contents, and S for subscription information. They also clearly indicate when the site was last updated.
Another resource is the University Law Review Project. The website is a collaboration of several universities and organizations. The last couple times I visited the site, the “full text search of law reviews” did not function properly. But the topical links do take the researcher to the Findlaw listing of law reviews on that subject. They also offer an email service to obtain abstracts on various practice areas.