If you missed last night’s airing of your favorite TV series, you don’t have to start phoning your friends in hopes that somebody, anybody recorded it. There’s a good chance you can watch it online, thanks to the growing number of Web sites offering full episodes of popular TV series. Some even have classic shows, so you can enjoy a stroll down memory lane with oldies but goodies such as Twin Peaks, the Love Boat, Perry Mason, and Alfred Hitchcock Presents.

Most of the major networks (ABC, CBS, NBC, and others) have online video libraries, as do many cable networks (Disney, TNT, USA, and more). There are also aggregators offering shows from many networks. Hulu may be the best-known, but AOL, TV Guide, YouTube, and Find Internet TV are also serving that niche.

Most online episodes are available free, with limited commercials. There’s often a time window in which a given episode is available, so don’t wait too long or you could miss the boat. You’ll need a fairly fast broadband connection and an up-to-date operating system; in some cases, it has to be a Windows OS (sorry, Mac users). You might also need a newer version of software such as Adobe Flash. Sites like Hulu spell out their requirements and recommendations, as does Disney.

If you can’t find a full episode, you can often fill in the blanks with a text synopsis of the show you missed or a few excerpts from the video. Happy hunting! —Eileen McCooey