Here is an ongoing list of articles addressing the issue of whether video games could be considered as art.
An interesting piece, not to define games as art, but on the position of games in art.
A very well-written explanation of how Roger Ebert's statements make sense, and what we can do about it.
An excellent article by Jason Rohrer, designer extraordinaire. This is very close to how I feel about the issue -- I believe games can have an artistic response, but we (game creators) need to step it up.