AWAKENING'TO his band to Joe's Pub "" MT.HAEL GrLrz "Spring Awakening." He met one of his best friends by spon- taneously performing a duet of a Broadway show tune at a high school house parly.</p><p> And his rock band, Old Springs Pike, devel- oped an early fan base by head- ing to Unitarian churches and performing raucous folk music at Sunday services.</p><p> But it's still going to take the 23-year- old actor a little while getting used to havingjust rocked the Tony Awards and winning a Best Featured Actor award for his shock-headed performance as Mori- tz, the doomed student in the critically acclaimed hit musical "The eight minutes after you win are some of the most ecstatic, unbelievable emotional moments I have ever experi- enced," says Gallagher, who jokes about taking his picture backstage with fellow wrnner Billy Crudup while trying not to cry He was most relieved about not em- barrassing himself "l knew there was anotherJohn in my category-John Cullum - so I prepared myself: 'Ifyou hen "John," don't go cra- zy, don't get up immediately, just wait for it and make sure you hear the last name "' He heard the last name he was hoping for, and now Gallagher - who has an upcoming role in the Kenneth Lonergan movie "Margaret" - finds him- self a sought-after actot even though he walked out of a "Spring Awakening" au- dition because he was more com- mitted to his rock band and didn't feel he belonged there Naturally, his success on Broadway will bring a lot more attention to Old Springs Pike, which perfoms at Joe's Pub tomorow night and at the Zipper Theater on W 37th St. in August Gallagher's parents are folk musi- cians, and he's a self-confessed "hamo- ny slut," so it's no surprise Old Springs Pike is a rootsy affair whose trademark covers include Tom Petty and Bob Dylan.</p><p> But they're not too cool to admit the band name came from the street one of them lived on, a name that had to be tweaked because it was too simila to BillyJoel's l97l debut album, "Cold Spring Harbor"Gallagher had watched his fellow bmd members perfoming in their om bmd in high school, tfuilled to heu other peo- ple embracing the sounds of Crosby, Stills md Nash and The Band Butthey were much older - 16, instead of I 5 - and it was a while before they all comected John bonded with Jmes Cleare by be- ing tutored in the importance of Billy Joel He md Heather Robb sprked after doing a duet of the Beatles classic "If I Fell " And James Smith was the guy Gal- lagher impressed by starting up that impromptu duet at a party. (Ihe song was from "The Se- I cret Gaden," a musical Smith I was perfoming for school.) Then theywent their sep- arate ways - as high school kids will - util the four mem- bers found themselves all livine in New York at the same time. "Of couse, the guitars came out and the nights of drinking md singing begm," says Gallagher "And three weeks later, we had three songs we were all really ex- cited about," Now Gailagher has a Tony; the bmd's steadily increasing fan base has a lot of new members, md Old Springs Pike has some new songs to perform Galla- gher is committed to "Spring Awaken- ing" though Novembe4 and the future - "Spring Awakening" in Inndon? An OId Springs Pike CD? - is wide open.</p><p> But one step at a time for Gallagher, who is still new enough to recognLe with awe, "Joe's Pub will be the biggest place we've played in NewYork!" a