Perhaps one of the best (worst) reviews yet:
http://chud.com/articles/articles/13364/1/SUNDANCE-REVIEW-THE-MYSTERIES-OF-PITTSBURGH/Page1.html
Highlights:
"Here's the big mystery of Pittsburgh: How did this movie manage to be so completely terrible?"
"Jon Foster, an actor so devoid of charisma that it seems like someone surgically removed his personality, is Art. The film is lifeless and inert from frame one, and it's not helped by the fact that Foster's voice over narration sounds like someone reading a grocery list."
"The Mysteries of Pittsburgh is a failure, a disaster, a joke whose punchline is making you sit through it all."