According to an article over on Cnet, Microsoft’s free Zune 4.0 software is now available for download, just in time as the Microsoft Zune HD officially goes on sale today the 15th of September.

New in Zune 4.0 is a new look, new Quickplay page, a Genuine-like Smart DJ feature which enables your Zune Pass subscription for an unlimited on demand music streaming experience, updated app store stocked with Zune HD movies, TV shows, and rentals.

Probably the most notable part of Zune 4.0 si Microsoft is giving Zune Pass customers a way of streaming music over the web via logging into their Zune net account from any PC or Mac computer.