Samsung took the unusual step of announcing a broad launch of its flagship Galaxy S Android 2.1 smartphone through all four national carriers and U.S. Cellular as part of a bid to boost its smartphone market share.

In the past, handset makers have usually offered flagship or high-profile models exclusively to a single carrier or granted exclusivity for a period of about six months. In this case, however, Samsung announced a rollout beginning July 21 at T-Mobile, with other carriers following. Carriers AT&T, Sprint and Verizon Wireless used such phrases as "upcoming availability" or availability "in the coming months" to describe their launch window. U.S. Cellular said its model would be available in the fall.

T-Mobile will charge $199 with a new two-year service agreement and data plan.

Samsung's rollout strategy, said The NPD Group's analyst Ross Rubin, "is unusual but not unprecedented." The BlackBerry Tour, he noted, was made available to both Verizon and Sprint. "The branding of the devices under different names while retaining the Galaxy S sub-brand," he noted, "is even more unusual, though, perhaps unprecedented, at least in the U.S."

 One reason for the launch through five carriers might be that Sprint and Verizon "have already committed to pushing signature exclusive devices relatively recently," Rubin continued. Those models are the HTC-made EVO 4G at Sprint and the Motorola Droid X at Verizon.

 With Samsung's launch of the Galaxy-class devices, each carrier will get a variation of the same handset for their 3G networks, with T-Mobile getting a HSPA+ version, AT&T getting an HSPA model, and Sprint getting a dual-mode 3G/4G version. Sprint's model will be the carrier's second 3G/4G phone following the recent launch of the HTC-made Evo. Each carrier's version will also sport a different name. T-Mobile's model is called the Vibrant. AT&T's is the Captivate. Verizon's phone is the Fascinate. U.S. Cellular's is simply called the Galaxy S.

 In other points of differentiation, the Sprint model will get a slide-from-the-side QWERTY keyboard and, like the Sprint Evo, two cameras. One camera will be front-facing for video chatting over data.

 All feature Android 2.1 OS, 4-inch multitouch touchscreen with virtual QWERTY keyboard, 1GHz Samsung processor, 720p high-definition video capture and playback, 5-megapixel camera/camcorder with autofocus and LED flash, six-axis sensor, stereo Bluetooth, DLNA-certified Wi-Fi connectivity, 2GB of embedded memory, and proprietary Super AMOLED LCD display for a thinner, brighter and less-reflective display. The phones will also access Samsung's Social Hub, which aggregates social networks, e-mail, contacts and calendars.

In addition, Verizon and Sprint said their models would be equipped with an embedded Wi-Fi hot spot, and AT&T, Sprint and T-Mobile said their models would access the Samsung Media Hub, which will be available "in the coming months" to download movies and TV shows from Paramount for rent or purchase. AT&T, T-Mobile and U.S. Cellular did not mention whether they would activate the Galaxy's embedded hot spot, and Verizon and U.S. Cellular did not say whether their models would access Samsung's Media Hub.

T-Mobile did say its Galaxy would come with included 2GB memory card loaded with James Cameron's "Avatar" movie, preloaded Amazon Kindle for Android app, MobiTV service to stream live and on-demand TV content over 3G, and Slacker Radio.

AT&T said its model would operate in 3G mode in foreign 2.1GHz networks and offer free access to AT&T Wi-Fi hot spots.