Apple unveils new iPod

Apple, the consumer electronics giant, on Tuesday announced new versions of its popular iPod music player.

The announcement was made by CEO Steve Jobs at a press event in San Francisco, which Apple dubbed "Let's Rock."

The iPod Nano, which comes with a video player, is thinner than previous models and slightly curved. Among other features, the display screen changes orientation from horizontal to vertical depending on how the user holds the device. An 8-gigabyte model costs $150, the same price as the original 1-gigabyte model from two years ago.

The Nano also features a new service called Genius, which recommends songs or movies based on a user's interests and creates playlists based on songs the user has chosen. The device will also shuffle the playlist if a user shakes it.

The announcement of a new line of iPods was widely expected. This time last year Apple announced the Touch, a touchscreen-only music player, and, the year before that, the Nano. The new products are timed for the holiday shopping season.

The move is considered critical to the future of the music devices as the iPhone, which comes with its own built-in MP3 player, threatens to make them obsolete.

As of July, Apple has sold more than 184 million iPods since their debut in 2001. Sales of the iPod, which once accounted for nearly 50% of Apple's annual revenue, were nearly flat last Christmas. Apple says the iPod has 73.4% of the portable music device market, according to NPD data.

All eyes Tuesday were also on Jobs' health. Jobs was treated for pancreatic cancer several years ago and has been looking surprisingly thin in recent appearances, unnerving investors. He looked as thin Tuesday as he did at his last appearance in June.

Apple (AAPL, Fortune 500) shares were flat Tuesday.