I said it before I read it...
"Cast Notes: (7/31/03) IGN FilmForce reported last week that Arnold Schwarzenegger's top choice to play Kon, Conan's adopted son, is Dwayne "The Rock" Johnson, although no official negotiations have started with The Rock.
this is before RR was onto it tho please reconsider!
Based Upon: (7/31/03) This movie will be the third film in the series that began with Conan the Barbarian in 1982 and Conan the Destroyer. Those movies were loosely based upon the character of Conan of Cimmeria as he originally appeared in early 20th century pulp magazine stories and novellas by Robert E. Howard (1906-1936), which were later collected as twelve paperback books, and starting in the 1970s, (partly) adapted in comic book form in two different titles published by Marvel Comics (which also featured new stories not written by Howard). Curiously, none of those original eleven books were called 'Conan the Barbarian,' 'Conan the Destroyer,' or 'King Conan' (though he was a king in the last few books). Of course, those twelve books were only partly written by Robert E. Howard, with L. Sprague de Camp and Lin Carter filling in gaps from Howard's original stories, outlines or notes. Besides the movies his work has inspired, Robert E. Howard himself was the focus of the 1996 Renee Zellweger/Vincent D'Onofrio romantic drama, The Whole Wide World.
all from: http://movies.yahoo.com/shop?d=hp&cf=prev&id=1808503058
This could all change... No doubt he will stick close to the original.
also another article confirming: