REALLY DEDICATED skiers begin to pray for snow in August when the ski shops have their sales.

In the past there was nothing to do during that long, dry period before the first real snow except bring the parkas down from the attic and have your ski bindings adjusted. Now skiers who have access to a VCR can get a vicarious thrill and even some help with their physical conditioning program by watching a variety of ski videos available for sale and rental at local ski shops.

Just for fun, you can rent one of Warren Miller's classic ski movies, usually shown at ski shows and resorts. He makes one every year (this year's, "White Winter Heat," was shown at the Warren Miller Ski Carnival at the Patriot Center earlier this month). Each year's version is slicker, faster-paced and more entertaining than the one the year before. Miller specializes in finding great skiers, daring camera operators and exciting locales for his humorous, thrill-a-minute shows.

A low-budget competitor of Warren Miller is Greg Stump who puts out "underground" ski movies with names like "Time Waits for (S)no(w) Man" and "Maltese Flamingo."

Once you are prepped psychologically, there is a surprising variety of videos designed either to teach you to ski or improve your physical condition long before the first snowflake falls. All carry disclaimers, that should be heeded, warning the viewer to consult a doctor or a ski instructor before attempting the exercises shown in the video.

Ski teaching in recent years has evolved from a left-brain activity, heavy on explanation and analysis, to a greater emphasis on right-brain activity, with a stress on relaxing and concentrating on how skiing feels. Two videos that embody the extremes are "The Alpine Ski School" for the left-brained, and "Ski Right" for the right-brained.

"The Alpine Ski School," filmed in chilly Killington, Vermont, progresses logically and systematically from instructions on how to put on skis and get on a lift to the most complex racing turns. It has a nonstop narration with long, wordy and often technical explanations of various levels of ski turns. Produced in 1982, the video dwells on certain skills that many ski schools no longer teach, but it is a good compendium of skiing techniques for the serious student (Embassy Home Entertainment, 76 minutes).

On the other end of the scale, for the devotee of "inner" or "holistic" skiing is "Ski Right" by SportsImaging. Aside from a very brief introduction calling skiing "a powerful form of self-expression," this video has no narration at all, just beautifully photographed pictures of very good skiers demonstrating perfect turns accompanied by new wave music. Instructions at the beginning suggest that a skier use his VCR counter to find on the tape the kind of turn he is working on and watch it sitting "in symmetry with arms and legs uncrossed." Each turn is illustrated at different speeds and camera angles.

The theory seems to be that just watching the video will make you a better skier, perhaps by osmosis. But many skiers are active people who may find it difficult to sit in their living rooms "arms and legs uncrossed" just watching beautiful and hypnotic pictures of a ski instructor doing the same turn over and over and over and over again.

For those of us who learn best using both sides of our brains, two recent videos have a nice mix of explanations and relaxation:

Warren Miller's "Learn to Ski Better," filmed in Snowbird, Utah, combines demonstrations by personable members of the Professional Ski Instructors of America with humorous skits to help you in "experiencing without analyzing." Many of these lessons, on subjects like "the fear factor," are introduced by "ski philosopher" Marcel Mogel, with a fake moustache and an indeterminate foreign accent. The funniest, intended to illustrate the wrong way to teach skiing, gives the learner's-eye-view of an uptight instructor explaining how to get off a chair lift. The explanation becomes more complicated and hysterical as the chair inexorably approaches the top of the mountain.

The video has good demonstrations with relatively clear and succinct narration, although some of the instructions, like "stay perpendicular to the slope," seem a little self-evident. There are very good sections on how to buy ski boots and tune up your skis. One inexplicable feature is the decision to place the instructions for beginners at the very end of the tape.

Ski magazine's "Learn to Ski," also takes a relaxed approach to teaching the basics of skiing. It starts, as it should, with the beginners' lesson, including putting on the equipment and walking on skis. The demonstrations are well done with some interesting skiers, like Jan Reynolds who skied down a 25,000-foot mountain in China and talks about skiing at high altitudes and physical conditioning. There is a useful "How it feels" section reviewing each important skill.

Some of the photography is inadequate, cutting off a turn, for instance, before it is complete.

On the other hand, the footage of Ken Read running the Hahnenkahn downhill race at Kitzbuhel, Austria, with accompanying commentary is by itself worth the price of the video. It's a real preseason thrill.

Unfortunately, the tape immediately drops from the sublime to the ridiculous with an embarrased Olympic racer, Susie Corrock, supposedly giving a racing lesson to "Moonlighting's" Bruce Willis who should have stayed at the Blue Moon Detective Agency (Karl Lorimar Home Video, 55 minutes).

The ski video that could have the best effect on your skiing, if you are inclined to exercise in front of the VCR, is "Suzy Chaffee's Ski Workout," by skiing's own Jane Fonda. Chaffee, a former Olympic skier, leads a balanced workout with stretching, warm-ups, an aerobic section (complete with reminders to take your pulse), exercises for specific muscle groups and a cool-down. With a few exceptions, the explanations are clear and the exercises well-photographed. (Today Home Entertainment).

These tapes can be rented or bought at area ski shops; regular video stores generally don't carry them. The Ski Chalet will allow you to take a tape free for three days; if you keep it more than that, you've bought it.

Terri Shaw is a member of The Washington Post foreign staff.