Ok, so we've all heard about the raging success of Apple's iTunes music store. Newsweek tells us we're an "iPod nation." But Apple is not the only game in town. One competitor in particular has garnered a devoted following by going in a different direction, ten dollars a month to stream any song or album in their catalog, any time you want. Some analysts think RealNetworks' Rhapsody service could represent the greatest challenge to Apple's early dominance in digital music.