While AT&T has confirmed the future availability of Samsung’s flagship Galaxy S III smartphone, the nation’s second largest carrier has not announced a release date. Last week it was reported that the device may be available on June 18th, but when preordering the handset as an AT&T Premier customer, the carrier indicates that the Galaxy S III will arrive “on or before” June 21st, Droid Matters reports. The highly anticipated smartphone will also launch on T-Mobile and Sprint on the same date. An AT&T spokesman declined to comment.