The movie web site now has two interviews online:
1) Sammy Sheldon, Costume Designer
2) Stephan Gessler, Assistant Art Director
The interview with Sammy focuses mostly on the costume designs for V, the military, and Evey. Stephan's interview deals mainly with the creation of the Guy Fawkes mask. Both interviews are well worth reading; it's nice to get an in-depth look at the production side of the movie.
You can visit the movie's website to find the interviews, or to read them "out of frame", click here.