Here’s an interview with Nick Goldsmith and Garth Jennings - producer and director of the Hitchhiker’s film - about the film’s cast and how they will translate Douglas Adams' work to the big screen. Overall, I find it pretty encouraging. Here’s a key quote:

“Jim: Can you tell us how youre going to be doing Zaphods other head? Do you think youll be able to improve on the BBCs effort? (link added)

</blockquote>

Nick: Theres no way anyone can improve on that! What are you talking about: you want more than that?”

</blockquote>

(thanks Stu)