Swedish music service Spotify just announced their application's submission to the iPhone App store. Similar to the company's Android application, the iPhone app gives users the ability to search for tracks and create music streaming play lists. One key feature of both applications is that it allows users to cache music for offline play. With this sort of functionality, it will be interesting to see if Spotify's app will be taken as a threat to iTunes. If this were the case, then Spotify's little green iPhone app might never make its way onto the device.

Often touted as one of the best music streaming services, Spotify's CEO Daniel Ek made a statement to the Register about his upcoming plans for a one-click download solution. This means that unlike other music applications like Pandora or Last.FM, the site would compete directly against iTunes as a store. As for the iPhone application, audiophiles simply select the tracks they'd like to listen to, and Spotify automatically syncs files to an offline playlist. This means that eager music fans can listen to their tunes from the subways, elevators and underground parking lots that normally plague their commutes to work.

This sort of ease-of-use is exactly why Spotify already celebrates an estimated 5 million member user base despite only being available in the UK, Sweden, Norway, Spain, France and Finland. The company already has European licensing deals with Universal, Sony, Warner and EMI and it solidified an American licensing agreement with the Independent Online Distribution Alliance (IODA) last week. The recent deal brings Spotify's catalogue to well over 7 million files. The company plans to launch in the US before the end of the year.