The companies are holding a press conference, starting at 12:30 p.m. EST, to announced the new smartphone, followed by hands-on demos at the Palm Lounge, located at Booth No. 435. Media and analysts who can't make the press conference live are invited by Palm to watch it live via streamed webcast.

Centro is the first Palm smartphone not fall under the Treo line. It sports the Treo's hallmark touch screen and QWERTY thumb-keyboard, however, but that's where the similarities end.

It is also supposed to be much smaller than a Treo, which are often maligned for their largish size, and is, in fact, the smallest Palm OS smartphone ever.

It is so compact, Gearlog's Sascha Segan, who had a chance to play with Centro during Tech Summit, described the keyboard as the tiniest he'd ever seen. So small as to be "infinitesimal" and "impossible to type on..with two thumbs." He described the keys as "little clear rubbery bumps," that rest underneath a curser pad and the standard Palm OS application buttons.

The smartphone, which uses CDMA cellular technology for Sprint's wireless network, supports the carrier's high-speed cellular-broadband EV-DO data network and is targeted at a younger demographic, those new to the smartphone space. From the sound of it that's about the only group that'll be able to use the keyboard without reading glasses or straining their eyes.

While no release date for Centro was announced, an unconfirmed report says it'll go for only $99 when it does ship. Sprint will have exclusive rights to the smartphone for 90 days, after which expect America's largest CDMA/EV-DO carrier and second largest mobile operator overall, Verizon Wireless, to pick it up.

Rumors say Centro would sport a microSD slot, a camera, and Bluetooth, all fairly standard in cell phones today.

Its small touch screen is supposed to run at a high 320 x 320-pixel resolution.

We'll report more details tomorrow.