The fourth generation iPod Nano is Apple's thinnest iPod to date and features a sleek new design with a curved aluminium and glass enclosure, available in nine colours.
As well as boasting a refined user interface and a high resolution portrait display, the new fourth generation Nano also features a built-in accelerometer, which automatically flips the image on screen to fit the way the device is held, and automatically goes into Shuffle mode when lightly shaken -- dubbed "Shake to Shuffle".
The iPod Nano incorporates Apple's "Genius" technology, which automatically creates playlists from songs in your music library that go together.
Steve Jobs, CEO of Apple, said: "The iPod Nano is the world's most popular music player and we've made it even better for this holiday season.
"We think users are going to love this amazing new design, the automatic Genius playlist creation, as well as automatically going into 'Cover Flow' with just a turn of the wrist."
Apple has also unveiled the second generation iPod Touch, which is smaller and lighter than the original with a contoured metal enclosure with integrated volume control buttons and a 3.5 inch widescreen glass display.
The company also revealed that iPhone and iPod Touch users have downloaded more than 100m applications from its new Apple Store since its launch on July 11 this year.
iTunes version 8 includes the Genius feature and for the first time offers television programmes in high definition for sale on the iTunes Store.
Genius highlights favourite songs in users' existing music library and also suggests related music on the iTunes store that they might want to add to their music collection.
In addition Apple has announced the return of NBC programming to the iTunes store including NBC networks' top 10 series available immediately to buy and download in both standard and high definition.
iTunes customers can choose programming from NBC, USA Network, Sci Fi Channel, Bravo, Sleuth and NBC News including popular shows such as 'Heroes', 'The Office' and 'Battlestar Galactica'.