Video of a presentation from Tara Fortune from the Center for Advanced Research on Language Acquisition. Great overview with benefits, models and the research.
Link to the website: http://www.mnimmersion.org/Benefits
Note: The video is approximately an hour long: Overview 0-12th minute, North Carolina experience 12th-30th, Louisiana experience 30th-36th minute, Oregon experience 36th-47th minute, summary 47th-50th minute, Minnesota needs 50th minute to end.