TO pro beach-volleyball fans, Stoklos and Smith are "Kings of the Beach." But from the looks of it, Miller Lite is truly king of pro beach-volleyball. At every tour location, spectators are bombarded with boldly lettered reminders of who makes much of the event possible.Miller Brewing Company, the main sponsor for the tour, pumps millions of dollars into the events each year. To get as much bang for the buck as possible, signs are plastered everywhere. Nets on each court are ringed with the words "Lite Beer," and the courts are surrounded by signs displaying the beer's name and the brand names of other sponsors. A sponsor since 1981, Miller now has a three-year, $6.8 million agreement with the Association of Volleyball Professionals. Other sponsors of the sport include Jose Cuervo Tequila, FILA sportswear, and Evian spring water. Skyrocketing prize money, made possible by Miller's extensive support, has helped beach volleyball expand and gain in popularity. Alcoholic-beverage companies are among the biggest sponsors of sports events. But some people are challenging the symbiotic relationship that has developed between sports and beer companies. In 1988, then-Surgeon General C. Everett Koop spoke out against alcohol companies' sponsoring and advertising at sporting events. This April, Louis W. Sullivan, secretary of health and human services, called on tobacco companies to stop sponsoring sporting events. He also asked citizens to consider boycotting them. Some activists hope he'll do the same in regard to alcohol companies. "By linking itself up with these healthy athletes, the alcoholic beverage industry is trying to buy 'innocence by association, says Patricia Taylor of the Washington-based Center for Science in the Public Interest. The Center coordinates a coalition of 60 organizations opposed to the promotion of alcoholic beverages through sports. "We make absolutely no statements in any of our promotional or advertising programs that link the consumption of our product with performance in sports," responds Miller spokesman Dave Fogelson. "Many of the people who drink our product are volleyball fans and fans of beach volleyball in particular. That's the reason why we are involved in the sport as a sponsor." "It's a tough issue for us," says player Karch Kiraly about the sport's financial dependence on alcoholic-beverage companies, "because nobody else wants to step up and support a growing sport." But, he acknowledges, "it would be healthy if we could diversify a bit."