Google has announced the culmination of its CR-48 pilot program: two Chrome OS-powered notebooks manufactured by Acer and Samsung. The machines were unveiled today during the second half of its annual Google I/O conference in San Francisco, and both "Chromebooks" share similar netbook-like specifications.

Acer's version will cost $349 with an 11.6-inch display, a dual-core Intel Atom processor, integrated dual-band Wi-Fi and optional 3G, an HD webcam with a noise cancelling microphone, two USB 2.0 ports, a 4-in-1 card reader, and one HDMI output. The 2.95lb device will reportedly offer up to six hours of continuous usage.

Samsung intends to charge a little more for its Chromebook with pricing set at $429 for Wi-Fi only and $499 for integrated 3G connectivity. That gets you a larger 12.1-inch display along with heftier battery that offers 8.5 hours of life, and those upgrades push the total weight to 3.26lbs. It also trades the HDMI port for Mini-VGA.

Both systems will be available for preorder on June 15 in seven countries: the US, the UK, Spain, Germany, France, Italy, and the Netherlands. Google also plans to offer a "Student Package" that will allow college students to pay $20 per month for a Chromebook and there could be similar plan for enterprise customers.

In addition to the Chromebooks, Google has teased a nettop running Chrome OS, unsurprisingly called the "Chromebox." Details are thin, but at least one model is in development at Samsung. Although it resembles Apple's Mac mini, the Chromebox is reportedly aimed at businesses and will come with various system admin tools.

While it remains to be seen if Google's cloud-centric operating system will gain traction, the company's web browser has witnessed continuous growth since launching in September 2008. During today's keynote, Google said Chrome is now actively used by 160 million people worldwide, up from the 70 million reported last year.