If there is one thing that the iPhone should implement is a way to stream Songs from your iTunes Library to your iPhone, they could even make it part of the Mobile Me service! Spotify an upcoming app for the iPhone does something very similar check out the article Time wrote about it.
If Spotify has its way, though, iPhone owners will no longer be slaves to iTunes, song-by-song payments or finite disk capacity. Last week the Swedish company behind Spotify's streaming music provider announced plans to release a free iPhone application that will let users listen to songs played directly off of its online service, with no need to download. That would give iPhone users instant access to any of Spotify's 6 million songs, without taking up precious memory space — way more than the maximum 7,000 tracks that a 32 GB iPhone can hold. Songs can also be temporarily stored, or cached, ready to play during those moments when Web connection drops, like when you're in a tunnel or underground. Spotify's new application could change the way iPhone users listen to music. But first it has to get the O.K. from Apple.
via Will Apple Open Up the iPhone to iTunes Rival Spotify? – TIME.