Today marks the official release date of Samsung’s new flagship Android smartphone, the Galaxy S III. In some countries, at least. The phone is now available in 28 countries around the world, but mostly just in Western Europe. Because the U.S. uses different network technologies than Europe, the phone’s release has been delayed in North America. There is not yet an official release date for a U.S. version.

Since most U.S. carriers use or are planning to implement 4G LTE networks, the Galaxy S III is not fully compatible with any U.S. carrier. The hardware inside the phones will be different from the worldwide version when it hits North America, with the phone’s quad-core processor replaced with an LTE compatible dual-core. T-Mobile, though, lacks an LTE network and Galaxy S III’s on that network could be closer to the version released worldwide today. Also, TmoNews is reporting that the blue version of the phone will be launching on T-Mobile in the U.S. on June 20th.

With Samsung rising in the Android smartphone market (and smartphone market as a whole), carriers are expecting the Galaxy S III to sell millions. Over 9 million pre-orders have been taken for the device. HTC’s only smartphone comparable to the Galaxy S III, the HTC One X, is available only on AT&T and Sprint in the U.S. With the Galaxy S III set to release on all U.S. carriers, Samsung is in a position to take a strong lead as the top Android smartphone manufacturer. That is, if they don’t run into the same import problems HTC is dealing with.