it's as legal as Napster was when it first dropped. it links you to a site that's hosting that particular movie, tv show, music video, etc.
peekvid.com was maybe the original, and got shut down with an injunction. however, unlike Napster, there's just too many of these sites right now for them to get shut down soon. remember how long it took the music industry to shut down Napster and Limewire, and those types of sites and programs never really went away. so enjoy, everybody!