When the United States Postal Service heard the grassroots buzz on electro-pop act the Postal Service, they didn't run out to buy the CD. Instead, their lawyers sent a cease-and-desist letter to the band's label, Seattle indie Sub Pop. But a year later, the government agency has not only put the suit on hold, they're also teaming up with the band for some cross-promotional marketing, which could include licensing a song for TV spots. ''Once they found out how we made the record using the mail, they got into working with us,'' says Postal Service's Jimmy Tamborello. ''Since [bandmate] Ben Gibbard [who's also Death Cab for Cutie's singer] and I live in separate cities, we couldn't really schedule a time to meet up and work. So we'd just send CDs back and forth through the mail.'' He adds: ''The mailmen are pretty dependable.'' As part of their deal, the band will perform for 800 USPS execs Nov. 17 in Washington, D.C. As for future promotional possibilities? ''I'd be up for a stamp,'' says Tamborello.