Pre-orders and previews underway ahead of launch.
Remote iTunes Streaming to iPhone or iPod Touch?
At present, iPhone or iPod touch owners must selectively sync content from their Mac or PC's iTunes library. This transfers those items to the mobile device for later playback. Apple is proposing that mobile device owners could instead access their entire collection over Wi-Fi or cellular networks:
New versions iTunes and the iPhone Software could theoretically eliminate this problem by syncing only the metadata -- or tiny files containing the barebones attributes of each media item or playlist but not the content itself -- from a user's iTunes library to their portable devices.Only a directory of the content would be copied to the device itself. When selected for playback, the device would remotely access the owner's Mac or PC to stream the content.
Apple presently offers similar functionality through their Apple TV and Airport Express, but these are limited to local Wi-Fi networks only. As with all patent applications there is no word on when or if Apple will implement these features.