Our friends to the North have a firm date for the Canadian version of the Samsung Galaxy S III. The Canadian carrier Videotron will be getting the SGS3 on June 20th. This could point to the North American launch in general, so it is possible the United States could be getting the phone on or around that same date. You can click on the source link below to check out Videotron's countdown sign-up page.
Source: S3Forums.com via Videtron