As rival Asus readies an update of its popular Eee PC, Hewlett-Packard on Tuesday introduced its own 8.9-inch notebook that weighs less than three pounds and a starting price of just under $500.

Like the upcoming Eee PC 900, the HP 2133 Mini-Note PC is targeted at students and road warriors. Both have 8.9-inch screens, but the Mini-Note includes a 160 GB hard-disk drive, while the Eee PC 900, set to ship mid-year, has a 12 GB solid-state disk drive.

There's also a difference in price. The Mini-Note, expected to ship this month, will start at $499. Pricing for the Eee PC will vary by country, but it will reportedly cost about $629 in Europe. Pictures of the Eee PC 900 are available on an Asus filing with the Federal Communications Commission.

The Mini-Note ships with the 32-bit version of Windows Vista Home Basic, while the Eee PC, which was unveiled last month at the CeBIT computer conference in Germany, will be available with either Windows XP or Linux.

Other specs for the Mini-Note include 1 GB of memory and a 1.2 GHz VIA C7-M ULV processor with 128 KB of L2 cache and an 800 MHz front-side bus. The Eee PC 900 is expected to run an Intel processor. Asus offers a 7-inch Eee PC today that is powered by an Intel Celeron processor.

The Mini-Note has 2 USB 2.0 ports, an integrated camera and Wi-Fi and Bluetooth 2.0 support. The machine weighs 2.8 pounds and its dimensions are 10 inches x 6.5 inches x 1 inch.

The success of the original 7-inch Eee PC has attracted its own competitors, such as Everex's Cloudbook, a $399 ultra-mobile PC introduced in January at the Consumer Electronics Show. On Tuesday, three of the top-selling notebooks on Amazon.com were Eee PC models.

Asus claims to have sold more than 350,000 Eee PCs since its introduction in October 2007. The Taiwanese company says it's on track to sell between 3 million and 5 million units by the end of this year.

With prices as low as $300, the 7-inch Eee PC has become a favorite of hardware hackers who have customized their machines with features such as an internal GPS and Bluetooth modules. While the original shipped with Linux, Asus has added Windows XP as an option. In addition, Microsoft Works and many of the Windows Live applications can be preloaded in the system.