As mobile-phone maker Motorola ( MOT ) struggles to end its downward spiral, Nokia ( NOK ) isn't the only rival causing problems for America's once-iconic wireless brand. The most immediate threat to Motorola, which saw sales plunge in the first quarter, comes not from Finland but from South Korea. Last year, Samsung Electronics passed Motolola to become the world's No. 2 player in the cell phone industry (BusinessWeek, 12/26/07). Now "it is in real danger of being overtaken" by LG Electronics, according to researcher Strategy Analytics.