MOVING RIGHT ALONG: Remember when the Pittsburgh Pirates adopted the Sister Sledge hit "We Are Family" as the team's theme song when the Pirates won the pennant in 1979? The Pirates are in the second division these days, but Sister Sledge has found a new powerhouse--the defending Super Bowl champs, the Chicago Bears, who have adopted a new Sister Sledge tune, "Here to Stay," as the team's theme. In fact, several Bears stars, including star running back Walter Payton and wide receiver Willie Gault, guest-star in the new video of "Here to Stay." It will be the first single from the sound track to "Playing for Keeps," a Universal Pictures film (due out Friday) about a trio of teen-agers who turn a run-down hotel into a (surprise!) rock 'n' roll resort. "It's about the hard work and struggle that goes into achieving your goals," said Gault, explaining why the team identified with the song. "We had to overcome adversity to reach the top, and now that we're here, we're here to stay. It's the same with the kids in the movie. They have to keep believing in themselves, and not give up, in order to make their dream come true."