In the old days, retail stores would rent VHS movies (and, later, DVDs). Customers would waste a good chunk of their evenings walking the aisles, browsing movie covers, asking teenage clerks for advice, and hoping a light would come on telling them that, yes, this is the movie to rent. Today, we do pretty much the same thing, watching preview after preview on our high-def television sets. Enter the free Internet Movie Database app for the iPad, or IMDb. The app lets you quickly access popular movie reviews, check out the actors, and read what people are saying -- all at your fingertips.