Apple's MP3 lead faces legal, technical challenges�|

Reuters.com writes about the potential threats Apple faces as it sits "at the top of the digital music heap." it seems that rivals from all corners of the earth are trying to deliver iPod and iTunes killers, from handset manufacturers to Microsoft and Amazon.com.

Mike McGuire at Gartner said, "These are all symptoms of what happens to a front-runner. It's almost harder to be the one on top than to be the challenger, because while challengers are building, the one on top is protecting and trying to extend the lead."

McGuire pointed out that "Apple must protect its existing iPod/iTunes business while at the same time figuring out how to transition to new products and services for the cell phone."