If you missed one of your favorite TV shows due to holiday travel, odds are good it is airing on the Web. Right now.

Are you a fan of crime drama? CBS.com offers full-length episodes of whatever flavor of "CSI" you prefer. Or if you want some old-school gumshoe work, go to Hulu.com for the '70s classic "The Rockford Files."

If you like comedy and missed the latest "30 Rock," it's at NBC.com. But if you miss "Alf," look for that funny alien at Hulu too.

I've been watching TV on the computer a lot lately, and it keeps getting better. Although the ads are more frequent, they are generally shorter than traditional TV ads. And since advertisers are afraid of chasing viewers away, they tend to be entertaining.

But online TV needs more work and more thought. There is no central depository for all shows, for instance, and some operators, notably sports-cable channel ESPN, have chosen a distribution model that limits access to the content even though it's free.

"We are at the intersection of a whole bunch of things" when it comes to TV on the Web, said Allen Weiner, a consumer technology analyst for Gartner Inc. and former newspaper TV critic. But mostly, "the content is in search of an audience and a business model."

That's why some networks, including NBC and Fox, are working with Hulu, while CBS and ABC have made their shows available on another site, Veoh.com. Networks also use their own Web sites to deliver shows.

There are great features across the Web. At CBS.com, I love "Live on Letterman," a series of clips featuring recent musical guests on the "Late Show." At Hulu, I can watch episodes of "Spider-Man" or "Speed Racer" with my son. And at ESPN 360, an online video channel from the cable sports giant, I've watched early matches from Wimbledon, Euro Cup soccer and, much to my surprise, a compelling cricket match between India and Pakistan.

TV on the Web is in its infancy, but it's growing up quickly, reaching a point where I expect to find video coverage online when a big event happens.

Consider the recent U.S. Open golf championship. Tiger Woods played Rocco Mediate in an 18-hole playoff for the title on a Monday - when most of us had to work - and I assumed someone would show the match. Sure enough, it aired on the site sponsored by the United States Golf Association as well as on EPSN 360.

Unfortunately, not all video on the Web is the same. The USGA broadcast was available to anyone with high-speed Internet access, but on ESPN 360 I could not watch unless I had the right Internet service provider.

Consumers can access ESPN 360 for free as long as their Internet service provider has paid ESPN. The model is similar to what the sports programmer has followed since its inception on cable TV.

With broadband Internet today, "people base their decision on speed and price," said Damon Phillips, a vice president with ESPN 360. "We think that will change, with content being the deciding factor."

I can access ESPN 360 because AT&T is my high-speed Internet provider. But if I used Comcast to go online, I would be out of luck.

"We are in active conversations" with Comcast, said David Preschlack, an ESPN marketing executive vice president, who added that ESPN 360 is available in 25 million homes.

ESPN defends its approach. "We think our content provides value" to both users and ISPs, Phillips said. "There's definitely a value to the content we have."

Online, the programming includes global "passion sports," Phillips said, including rugby, cricket, soccer and even polo.

In the fall, ESPN will air up to 20 different college football games each Saturday from every major conference. Many of those games will air on cable TV as a pay-per-game option but offered for free online.

According to Move Networks, which provides the technology that delivers online TV for ABC, FOX, ESPN and others, online viewership has increased 50 percent over the last 6 months.

"We've been growing at more than 100,000 people a day, on average, since March," said John Edwards, CEO of the Utah firm. To watch TV on ABC.com, users are required to download a small plug-in tool that accesses the content.

It works on all major Web browsers, Edwards said. I've never had a problem watching an online TV show that required such a plug-in. On the other hand, I have had issues trying to use Joost, another online TV service that requires a more robust download and registration process.

Move's plug-in tool has been downloaded more than 40 million times so far, meaning at least that many people are enjoying online TV from its partners. The tool also offers a better viewing experience. Hit play and a show starts instantly, and there is no annoying buffering.

Hence, such technical improvements are spurring more viewership, Edwards said, and it's convincing networks that the audience is growing.

People usually use the Internet to "catch up" on shows they have missed.

"You don't abandon a show because you miss an episode," said Weiner, the analyst. "The research is showing this is more of a benefit to a network."

Another benefit: The catch-up audience "is providing a solution to the DVR advertising problem," Edward said, noting that people don't seem to mind the short advertising breaks inserted into network programming.

With a digital video recorder, or DVR, viewers can skip commercial breaks. Online, well, at least the ads are short.

The biggest competitor to online TV remains sites like YouTube.

When George Carlin died last month, people streamed to the Web to find clips of his routines.

At Hulu, you could watch Carlin's monologue from the very first episode of Saturday Night Live, which he hosted on Oct. 11, 1975. That's a poignant piece of pop culture and a great example of what television on the Internet can offer - unique, timely content ready to view when you want to see it.

But was it Carlin's best material? Of course not. It was a clip from a network TV show. For his famous wordplay, one went to YouTube, where multiple versions of those "seven dirty words you can't say on television" were available.

Some things are still taboo for TV, no matter where it's aired.

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PRIME TIME, ANYTIME

NBC.com: "30 Rock," "The Office," "Heroes," "Tonight Show"

CBS.com: "CSI" (all versions), "Swingtown," "The Price is Right"

ABC.com: "Ugly Betty," "Grey's Anatomy," "Samantha Who?"

Fox.com: "The Simpsons," "House," "Bones," "Family Guy"

Hulu.com: Classics including "The A-Team," "Barney Miller," "Miami Vice"

SPORTS

ESPN 360: Live coverage of European soccer, Wimbledon tennis, college football

MLB.TV: Subscription based, but access to every out-of-market major-league game

Olympics: NBC will stream live events and full-event replays at NBCOlympics.com. A special video download will be required.

KIDS

NickJr.com: Full episodes of "Dora the Explorer," "Wonder Pets" and "Blues Clues"