NEW YORK (Money Magazine) - Visit an electronics superstore these days and you'll see the phrase "high-definition television," or HDTV, everywhere. But you may not be sure what HDTV is - let alone how, as the teenage sales reps at the store say, "it's gonna change your life."

At this point it's becoming increasingly rare for manufacturers to offer family-size TVs (bigger than 27 inches, say) that aren't HD-compatible, but the upside of this remains, for the most part, hidden behind a veil of confusion. You have five - yes, five - different HDTV technologies to choose from and three different ways to bring the signal into your home, each with its own receiving hardware and service charges.

The puzzlement doesn't always end when you bring the TV home, either.

There are roughly 10 million HD sets already in American living rooms, but only 5 million actually receive high-definition programming, according to Yankee Group analysis. (And if you think cost is what's holding back those other 5 million, think again: Bringing HDTV signals into your home doesn't necessarily mean blowing your budget.)

So you probably have some questions, like. . .

Absolutely - this isn't an emperor's-new-clothes experience. Each standard television frame is made of 480 horizontal lines, compared with either 720 or 1,080 lines with HD; the latter is as much as six times sharper. HD is also wide-screen, with the same proportions as a movie screen.

Even at a distance, HD picture quality is striking. The Price Is Right may not be terribly compelling, but watching the Super Bowl, Saving Private Ryan, or The Sopranos in HD can be a vivid experience.

You bet. NBC, ABC, CBS, and PBS, along with HBO, Showtime, and Discovery have broadcast in HD for several years. UPN, WB, and Fox are beginning to offer it, as are cable channels like ESPN, TNT, Starz, Cinemax, Bravo, Fox Sports Net, and NBA TV. New specialized HD channels are also appearing, most notably HDNet and HDNet Movies, which broadcasts original specials and sporting events, as well as films. Among the wide variety of programs showing in HD are The Tonight Show with Jay Leno, Law & Order, CSI, Everybody Loves Raymond, Smallville, Six Feet Under, Monday Night Football, the NBA Finals and last summer's Olympic Games. "It's the most watched percentage of television," says Yankee Group analyst Adi Kishore.

There are three ways to receive an HDTV signal: cable, satellite, and "off air," via an old-fashioned antenna. Cable is the best - it offers a wide array of local programming and has enough bandwidth to rapidly add new HDTV channels.

What's more, for cable subscribers who already get digital service (which averages about $50 a month before premium channels, plus a set-top box rental fee of up to $7 a month), a move to HD often costs nothing. You just swap out your existing digital cable box for an HD-enabled one. Basic cable users can sometimes get an HDTV upgrade from their cable provider for the cost of the box rental alone, but often it makes sense to upgrade to digital cable at that time.

Look to the sky. Satellite TV providers, DirecTV and Dish Network, offer HD versions of HBO, Showtime, ESPN, Discovery, HDNet, and HDNet Movies, with a few additional pay-per-view channels and some network content. DirecTV also has the NFL Sunday Ticket, which broadcasts more than 100 regular-season games in HD, for $220 a season. In general, satellite services can't offer as much local programming in HD, since the local channels they do carry - which must be transmitted to a satellite, then beamed back to earth - strain their bandwidth.

The cost adds about $10 or $11 a month, on top of the monthly service bill that can range from $30 to more than $90. If you're starting from scratch, you'll need a dish (installation fees are often waived these days) and a receiver, which usually costs $300 to $400 to buy, though Dish Network leases it as part of the monthly service fee.

Cablevision's Voom, the newest satellite provider, grabbed attention with a very large offering of HD programming. It features 21 of its own commercial-free channels, feeds of movies, sporting events, concerts, cartoons, and news. Its monthly service fees range from $50 to $90, depending on premium channels, plus an equipment rental fee of around $10.

Yes - and it's free. Old-fashioned broadcasting still goes on, now with digital signals including HDTV shows. If your TV has a built-in HDTV tuner (also known as an ATSC tuner), you can buy a digital antenna for under $100, install it, then hunt for a signal just like in the old days. If the TV doesn't have a built-in tuner - and many HD-ready sets, intended for use with cable and satellite connections, do not - you can buy a receiver box that includes an HD tuner for $300 or less.

Since satellite TV boxes include an HDTV tuner, you can often connect an off-air antenna to that to receive locally broadcast HD channels. Voom's $200 installation even includes one.

Yes, but not with a VCR. The newest frontier in high-def perks is an HD digital video recorder. The benefits of DVR, the most famous of which is TiVo, have been sung many times: You sift through weeks of programming for the real gems, then watch them at your leisure. With satellite, purchasing an HD DVR is the only option, at a steep $1,000. Cable subscribers have it easier: In some areas you can lease one in place of a digital cable box or standard DVR, often at no extra cost.

Like high-definition television, of course, DVRs are frequently said to be able to "change your life." Imagine putting the two together.