Microsoft's Zune has been out for a while now; as early as November, 2006, with a couple revisions in between. So far they've sold over 3 million units in total, and perhaps Microsoft is about to step up the game to compete further with Apple's iPod. Engadget is reporting that word has come from Microsoft itself that new Zune hardware will be available this year.
So far, details are extremely slim on what will be released. How slim? Very slim. All there is to work off so far is a Tweet from Brian Seitz, a member of the Zune team. It's implied that at least one new model will be available by the years end, but it's expected there will be more than one, obviously.
So, at the moment, that's all we know, but now that those details have come out expect more information shortly.