Don't be fooled by Halle Berry's résumé, which reflects the typical evolution of an American bombshell: cheerleader, prom queen, first runner-up for Miss USA 1986. From the looks of it, it seemed only a matter of time before the 23-year-old actress would progress to a starring role in, say, Spring Break: The Final Chapter. Instead, Berry, a broadcast journalism major at Cuyahoga Community College in her native Cleveland, made her movie debut as a foulmouthed crackhead in Spike Lee's Jungle Fever. ''I wanted to do a film first that would prove that I really am an actress,'' she says, ''so I wouldn't get stereotyped right off as just another pretty face.'' To play a junkie, Berry talked to about 80 recovering addicts and even toured crackhouses with an undercover officer. ''It was a real stretch for me,'' she says. But don't expect her to be typecast now. She'll next play an ambitious downtown club kid in the fall comedy romance Strictly Business and an exotic dancer opposite Bruce Willis in the Christmas action flick The Last Boy Scout. One thing's for sure: This beauty queen is no dope.