"What's the story, morning glory? / What's the word, hummingbird?" That was Broadway teen talk back in the early '60s, when the high school kids in Bye Bye Birdie gossiped about their friends in a game of telephone tag. More than 40 years later, another band of gossipy girls is peeking out of another set of windows on a Broadway stage. How far have we advanced? Well, the kids are in a college sorority now, and the squeals of excitement--and the title of the opening song--have evolved into dumbed-down Valley-speak: Omigod You Guys!