Go West, Young Men

After five nights of concerts at London's Wembley Arena, the office of Westlife tour manager Anto Byrne looks like a charity shop. There are crates of fan mail. Piles of stuffed animals. And underwear — boxers, briefs, Calvin Kleins, a pair that says "Babe Magnet." Enough, says Byrne, so that "none of us ever have to buy it ourselves."

If only they could get Americans to give them underwear too. In less than three years, the Westlife guys — Nicky Byrne, 22, Shane Filan, 21, Kian Egan, Mark Feehily and Bryan McFadden, all 20 — have become fixtures...