Two of this spring's biggest hits are already being prepped for sequels and a "journey" long anticipated may be on hold. 

Happily for the growing legion of "How To Train Your Dragon" fans, DreamWorks Animation CEO Jeffrey Katzenberg announced on a call with investors on Tuesday that a sequel for the critically acclaimed 3-D hit is in the works.  Katzenberg admitted he was concerned about the film's smaller than expected $43 million opening, but calling the film "beloved," he noted its well on its way to matching "Kung Fu Panda's" $215 million gross.  The studio is also developing a live show, TV series and online virtual world  for the "Dragon" franchise (Katzenberg wasn't jinxing the expected Best Animated Film Oscar nod).

Somewhat more surprising is the news that a second installment of "Clash of the Titans" is being developed.  According to Deadline.com, the urgency around a sequel to the worldwide blockbuster is to shoot it before star Sam Worthington has to return to Pandora in "Avatar 2" (does Warner Bros. know something about this that James Cameron doesn't?).  "Brothers and Sisters" creator Greg Berlanti, who wrote and is producing "Green Lantern," is responsible for fashioning a story for "Titans 2," but won't write the screenplay.  Director Louis Leterrier will not return.

The trade blog also reported that the long in the works second installment of "Journey to the Center of the Earth" is still at the gate.  Warner Bros. and Walden Media want to hit a fall 2011 release date, but star Brendan Fraser is considering dropping out if original director Eric Brevig doesn't return.  Brevig is currently busy with WB's "Yogi Bear" and seemingly unavailable. Fraser, who could be facing his third bomb in a row with "Furry Vengeance" this weekend, is resisting the studio's suggested replacements for Brevig. He may want to re-consider as the sequel may move forward without him and be fashioned around his now grown up co-star Josh Hutcherson.