Greetings, Mark,
Aaron Smuts has done some nice work on this issue (in which as I recall the notion of interactivity plays a crucial role). You should check out the following articles of his:

"Are Video Games Art?"  Contemporary Aesthetics 3 (2005): 1-15.
"What is Interactivity?" Journal of Aesthetic Education 43.4 (2009): 53-74.



Adding to Aaron's street cred is the fact that Roger Ebert recently twittered (tweeted?) a link to the latter article.


Hope this helps!