Nokia (NYSE: NOK) may be the world’s dominant handset maker, but Motorola should be more worried about its fleet-footed Korean rivals, LG (SEO: 066570) and Samsung, according to an in-depth Businessweek feature. As the article points out, in the US, where Motorola remains number one, Nokia has actually lost ground—with its market share dropping by nearly two-thirds in the last two years. LG and Samsung, on the other hand, sell well in US, with their combined sales matching that of Motorola (NYSE: MOT). They’re also doing well outside the US, where Motorola is seeing its market share all but implode. Research firm Strategy Analytics even believes LG, now the world’s fourth largest handset maker, will bypass Motorola, currently clinging to its number three position, having leapfrogged last year over Sony (NYSE: SNE) Ericsson, now in fifth position.

What’s the secret to their success? It’s LG and Samsung’s ability to constantly churn out new, stylish handsets with the latest technology—rather than a single mega-hit like the RAZR. In the second quarter alone, Samsung is trotting out 30 new multimedia models. They also do well in working with networks to tailor their handsets to specific target audiences. LG meanwhile, has been good at bringing out cutting edge technology before anyone else—and in fact, had the first touch screen phone, even if iPhone often gets the credit for popularizing it. Moreover, the Razr’s decline has often been blamed on LG and Samsung quickly coming out with their own versions of Motorola’s hit handset. Finally, the Korean device makers are benefiting from the weak Won, especially compared to Nokia and Sony Ericsson (NSDQ: ERIC). The only real hurdle is whether or not LG and Samsung can continue on with the “breakneck” pace they’ve set for themselves.