According to Amazon, It looks like the first episode of Peter Jackson's trilogy will be available on Blu-ray and Blu-ray 3D on March 19, 2013. You can make your pre-orders on Amazon's website. I remember when any installment of Lord of the Rings came to DVD we had to wait till the following summer to have access to the movie. Lucky us!
Specs and supplements have yet to be revealed, but suggested list price for the Blu-ray is set at $29.98. No 48FPS release has been hinted at and for obvious reasons. Maybe we'll see it re-released in 4K when there is an official 4K format and hardware has built in support for 48fps material.