Some day soon, the television and the personal computer will be nearly indistinguishable.

	Mary Ellen Matthews NBC's Web site offers all episodes of the comedy "30 Rock," starring Alec Baldwin, left, Tina Fey and Tracy Morgan. Plus, Fey answers readers' questions. Click photo for larger image.

It's happening before our eyes. We're able to time-shift when we watch "Heroes" on our digital video recorders, and we're sneaking peeks at snippets from last night's "Colbert Report" on YouTube. To say nothing of downloads for our iPods.

Not one to overlook an audience (or a revenue source), the networks are taking their first steps in streaming video of old episodes of our favorite shows. We took a quick tour of the networks' sites, and here's what we found.

But first, a couple of notes: Some of this content is changing daily, so what's here today may be gone later today. Plus you'll need a broadband or high-speed connection. And sometimes even that's not enough to watch the videos uninterrupted.

NBC

Full episodes of NBC's shows can be found on NBC.com, but the network also offers highlights, previews, replays and a load of Web-only content.

To get to the full episodes, you'll click on "video" and scroll down to "NBC Rewind." In addition to select episodes of "Heroes," "My Name Is Earl" and "Friday Night Lights," full seasons of "30 Rock" and "The Apprentice" are available.

The network also has previews of the upcoming dramas "The Black Donnellys" and the noir "Raines," starring Jeff Goldblum. The previews and 2-minute replays can be found by clicking on "NBC 24/7."

The network's collection of Web exclusives is extensive and beats the other networks hands down. The stars of "Heroes" talk about their characters; Tina Fey of "30 Rock" answers reader questions; and the characters Dwight and Kelly from "The Office" keep hilarious blogs.

NBC had a legal row with YouTube.com after fans sent copies of the "Lazy Sunday" skit from "Saturday Night Live" to that site. Now NBC has its own sketch material neatly placed here. Some "SNL" sketches still sneak up on YouTube as well as a growing number of parodies of "(Blank) in a Box."

ABC

ABC.go.com goes all out with full episodes of "Grey's Anatomy," "Desperate Housewives," "Lost," "Ugly Betty," "Brothers & Sisters," "What About Brian" and the new "Knights of Prosperity."

It also previews ABC shows and ABC Family programs such as "Lincoln Heights."

Launch the Full Episode Player on the lower right-hand side of the opening splash screen.

Naturally full episodes can take long load times. We were able to watch some "Lost" episodes but only after going through several pop-ups and a lot of clicks that seemed to suggest something was wrong.

CBS

A recent CBS study showed more than half of those surveyed knew they could find full episodes of network shows on CBS Innertube on CBS.com.

But in addition to recent episodes of all the "CSI" shows, "Shark," "The Unit" and "Numbers," Innertube has originals such as "Animate This!" "BBQ Bill," "InTurn" and "The Papdits" from the writer of the "Borat" movie.

We watched episodes of "Jericho" and "Shark" with no problems. In fact, CBS's streamcasting seemed to work the smoothest.

CW and Fox

The CW just announced it would have full episodes at video.cwtv.com. There are select episodes of "Veronica Mars" and "One Tree Hill," but, strangely, no "Smallville." It was also offering "Beauty and the Geek" ... if you can get the site to work. It took several attempts to watch an episode of "Veronica Mars." The stream kept breaking.

Fox has interview clips but no complete episodes of its shows at Fox.com. Instead some Fox shows can be found on myspace.com/fox. Entire episodes of "American Idol" are available on americanidol.com the day after they air, and snippets are available thereafter.

Cable channels

HBO.com is heavy on video previews of any of its programs. Podcasts are available for HBO and Cinemax originals, and there are constant reminders that the day after a show like "Rome" airs, it's available through HBO On Demand if you have digital cable.

There isn't much video on Showtime's site, SHO.com, but there are podcasts of interviews with the stars of their shows, such as "Dexter" and "The L Word." Also check out the "Weeds" mini-site for some choice songs for your streamcasting enjoyment.

MTV.com allows you to see entire programs such as "Subterranean on Overdrive" and that day's "TRL" video countdown.

Comedy Central's Motherload site has clips of segments of "South Park," "The Daily Show" and "The Colbert Report." The site does have a habit of slowing load times.

Old TV

America Online's "In2TV" (television.aol.com/in2tv) offers vintage shows, from "Adventures of Brisco County Jr." to old Looney Tunes.

Video.google.com promises shows from a multitude of sources. A recent search turned up a ton of Charlie Rose interviews. Some TV shows, ranging from "CSI" episodes to basic cable fare like "Campus Ladies," will cost $1.99 to download.

The Museum of Broadcast Communications in Chicago (museum.tv) has some great old news shows, from a montage of D-Day coverage from NBC to a tribute to Yvonne DeCarlo.

PBS offers more than 50 episodes of its "Frontline" programs at pbs.org/frontline.