There is a Lion King Eight-Disc Trilogy Collection box set that contains all three Lion King movies. According to Amazon.com, it is slated for release on October 4, 2011, the same day as The Lion King Diamond Edition is set for release. So, the answer is yes, but they come in a collection box set.
It will be released on October 4, 2011.
The Blu-Ray version will be out on October 4, 2011, so the DVD version should be out with it.
The Lion King will be coming out of the Disney Vault in fall 2011; there is an official trailer that states this. However, there is no official date of its release.
It was released as a "Special Edition" from the Disney Vaults in October 2004 with higher quality, bonus features, and deleted scenes. But, it was put back into the Disney Vaults in January 2005.
It is unknown when the vault of King Djoser was robbed. The only remains left in the vault was a mummified foot.
King Creon - 2011 was released on: USA: 2011
Turnaround King - 2011 was released on: USA: 19 June 2011
Sandwich King - 2011 was released on: USA: 21 August 2011
The Last King Blood - 2011 was released on: USA: 2011
When I Was King - 2011 was released on: USA: 4 February 2011 (Dallas, Texas)
If you are referring to a sequel to The Lion King II: Simba's Pride, then, Disney has not announced that it is in production so it won't be coming to DVD anytime soon. However, The Lion King 1½ was marketed as The Lion King 3 to those who live outside of the United States and Canada and was released in 2004.
Bringing King to China - 2011 was released on: USA: January 2011