was able to obtain a leaked screenshot from an internal computer system that might just give us the answer. The screenshot shows what might be a newspaper or magazine ad that will soon be viewed by Canadian readers. On the bottom of the ad is a list of some of the major Canadian carriers that will be carrying the phone, and above that, the ad reads "Pre-order Today. Available June 20th". You can't get any clearer than that.
Of course, since this was spotted on a computer screen instead of in a newspaper or magazine, it isn't exactly written in stone. Still, it might behoove those up in Canada to circle the date on their calendar and keep an eye out for the start of pre-orders. And for those in the U.S., this date might reveal a time period when we could see the U.S. version of the Samsung Galaxy S III get released.