Hewlett-Packard on Tuesday unveiled five business notebooks and initiatives to help corporate users stay connected everywhere they go.

The biggest spotlight at the HP Mobility Summit in San Francisco was on the smallest new notebook, the HP Compaq nc2400 Notebook PC, which is less than 1 inch (2.5 centimeters) thick and weighs less than 3 pounds (1.36 kilograms). It includes a full-size keyboard and an internal optical disc drive.

The company also rolled out the HP Compaq nc6400 Notebook PC, which is based on Intel Core Duo processors and can be equipped with modules for two types of third-generation (3G) mobile data modules. An evolution-data optimized part will be available when the PC ships in mid-May, and a high-speed downlink packet access (HSDPA) module will come later this year, the company said.

The company has teamed up with Vodafone Group to integrate the mobile operator’s 3G service, based on HSDPA and universal mobile telecommunications system, into the nc6400 and cooperate on future notebook designs, HP said. The systems are designed to support international roaming in many countries.

Mobile devices and applications are the key to future IT growth, said Todd Bradley, executive vice president of HP’s Personal Systems Group.

"As we look to this next phase of growth, clearly we see it driven by mobility, clearly we see it driven by connectivity, and we believe that HP has an enormous set of assets to bring to bear," Bradley told reporters and analysts at the San Francisco event, where HP kicked off a marketing push that includes new mobile consumer devices and advertising as well.

Notebooks are leading the growth in HP’s PC business. "Our notebook business is smoking hot," said Ted Clark, senior vice president and general manager of HP’s Notebook Global Business Unit.

The company’s notebook business grew 54 percent since last year, and HP has gained almost 2.5 percentage points of market share over the past year, he said.

Built-in 3G capability, which HP first introduced in products last year, is a key business feature, said Creative Strategies analyst Tim Bajarin. Offering two different types of 3G technology, used in different parts of the world, could be even better for some executives, he said.

"The freedom to have the ability to connect anytime is really critical," Bajarin said. "We’re moving to a much more global IT society in which working in just one location isn’t the norm anymore."

Also in the lineup Tuesday was the HP Compaq 4400 Series, which converts from a notebook to a tablet PC and will be available in early June for US$1,649. The series is based on Core Duo chips. HP also unveiled two systems with 15.4-inch widescreen displays. The nx7400 is based on Core Duo processors and starts at US$749. The 8400 series, a desktop replacement with ATI Technologies graphics and an antiglare screen, starts at $1,599. Both are set to ship in mid-May.