The first official announcement has been made. The Lord of the Rings expanded editions will not be one box set, but a three separate releases that will be staggered over the course of the next year, according to Jeff Bond. The Fellowship of the Ring will be a three CD set with an additional DVD that presents the score in 5.1 (although the audio format - whether it will be in DTS, DVD-Audio or Dolby Digital - is unclear at the present time).
The set will be released on November 22. The release dates for The Two Towers and The Return of the King have not yet been announced, but Jeff Bond assured us that we should have everything within a year, and his book on the scores is coming out in 2006.
While a box set was originally expected, the staggering of the releases is actually a good idea from a sales point of view; while I would have liked to have all the music as soon as possible, it is certainly going to make less of an impact on my wallet at once this way.