With its hand forced by a retail partner who it says inadvertently leaked details before its planned announcement date, Microsoft today confirmed several major upgrades to its Zune device in a surprise announcement the day before Apple is set to unveil new iPod devices.

That the new Zune would be a 120 GB device is no surprise. Raising eyebrows, however, are two newer features—one that allows Zune users to buy and download music from any WiFi hotspot, and another that lets users tag songs heard on participating FM radio stations for subsequent purchase.

The “Device to Cloud” feature simply lets Zune owners browse and buy from the Zune Marketplace directly. Previous devices used the on-board WiFi feature only to share songs between other Zune owners.

“Buy from FM,” meanwhile, lets customers tag and buy songs from the Zune’s FM receiver. When in WiFi range, the song can be downloaded immediately. If not, then the device will download the song when in range, or when docked to the home computer.

Other updates include a new song recommendation system, which includes the “Channels” feature that lets Zune users listen to genre-specific playlists pre-programmed by music industry critics. Other recommendation services include software that picks new music based on previous usage, and an online music social network called the Zune Card (which went live with an existing app that is now available for syncing via WiFi.)

All features are set to go live on Sept. 16 to both the new devices and existing ones via a firmware and software update.