Just one week after its introduction, Apple’s iPod shuffle is in such heavy demand that the company’s online store is quoting a wait of two to four weeks for the device. “The backlog of orders comes not quite a year after the introduction of the iPod mini sparked a a six-week wait when ordered online. There is a two- to three-week wait for the $99 iPod shuffle, which holds about 120 songs, while customers face a wait of three to four weeks for the $149 model, which has double the capacity, according to the Apple Web site.”