Slacker has finalized publishing agreements with major music labels so it now "officially" has the content rights allowing users of its online service to transfer songs onto Slacker Portable Radio Players.

The publishing license agreements, which were completed prior to the availability of Slacker Portables, also enable Slacker Premium Service customers to transfer songs and replay them whenever they want.

EMI Music Publishing, Sony/ATV Music Publishing, Universal Music Publishing Group and Warner/Chappell Music are all working with Slacker radio. They even were kind enough to throw in some quotes for the press release, so you know they're especially happy about this deal. (And, I suppose, anything that helps chip away at Apple's digital music dominance will make the RIAA happy nowadays.)

Starting today, the Slacker Portable Radio Player will be allowed to instantly access hundreds of thousands Wi-Fi hotspots nationwide that normally require a password or web-based login.

Slacker has hooked up with Devicescape to enable this functionality. Essentially, Devicescape automates the process of accessing Wi-Fi hotspots so Slacker users can update their personal "radio stations" places like Starbucks and McDonalds.

Current owners of the Slacker Portable Player get the Devicescape functionality through a free firmware update (available today). Simply refresh your stations to automatically update all existing players.

All new Slacker Portable Players will ship enabled with the latest features, of course.