SFX - Dark Crystal 2: it's official!
http://www.sfx.co.uk/page/sfx?entry=dark_crystal_2_it_s
"The Jim Henson Company remains committed to producing Power of the Dark Crystal."
Sci Fi Wire -- Dark Crystal Sequel Announced
http://www.scifi.com/scifiwire2005/index.php?id=31032
"The Jim Henson Co. announced that it will produce a feature-film sequel to its 1982 fantasy film The Dark Crystal, with the working title The Power of the Dark Crystal."