AFTER MIA HAMM LED THE 1996 U.S. Olympic women's soccer team to gold medal victory in Atlanta last August, endorsement offers for Nike, Pert Plus shampoo and Power Bar flew in at goal-scoring speed. But the star forward remains much more interested in her kick than her coif. "If I had to give up what I was doing, I wouldn't be happy," says the fresh-faced 25-year-old, adding, "It's weird getting attention. When companies want me to represent them, I think, 'Why me?' " Easy, says her Olympic teammate Julie Foudy: "Mia has natural beauty. It's not something she has to spend $1,000 on." Confirms Hamm's husband, Christian Corey, 24, a second lieutenant in the U.S. Marine Corps stationed in Pensacola, Fla.: "She doesn't spend a lot of time in front of the vanity. She puts her hair up and off we go, which is good because it makes it easier to get to places on time." Besides, Hamm's first brushes with beauty treatments haven't been pretty. For one ad, "they cut and colored my hair with reddish highlights. My scalp was burning," recalls Hamm, who had never had her hair dyed before. But the 5'5" athlete is adjusting to the spotlight. She just decided to buy another tube of lipstick. "I have two colors," she says brightly, "and thought I needed another."