Correct....
Children of Dune is the continuation of Frank Herbert's Dune (2000, mini-series by Sci-FI Channel). The story deepens after the end of previous mini series, which was based on "Dune Messiah" and "Children of Dune" (the 2nd and 3rd books of Dune Chronicles by Frank Herbert). People might feel confused about the story if they didn't watch the first Dune mini-series before. The dvd (2-discs version) of Children of Dune will come out at May 20. It might be possilble that a Director's cut Edition would also come out in the future, just like the 1st Dune mini-series(a 2-discs version and a 3-discs DC version)

Here are the links about Children of Dune and Frank Herbert's books
The Official Children of Dune Website
The Official Dune Novels Website

The release date of Chlidren of Dune DVDs came from The Digital Bits

PS: Frank Herbert's Dune Chronicles was composed by:
Dune
Dune Messiah
Children of Dune
God Emperor of Dune
Heretics of Dune
Chapterhouse: Dune

Dune Prequels by Brian Herbert(son of Frank Herbert) and Kevin J. Anderson:
House Atreides
House Harkonnen
House Corrino

It looks like someone typed the names of those books faster than I do....