Here is a compilation of links to individuals and their writings on the Fair Tax. It appears to me many economists are skeptical of the plan (though more supportive in general of consumption taxes relative to income taxes for efficiency reasons). I have been able to find a few prominent economist, though, supportive of the plan.
One question I have not seen answered is this: what would happen to fiscal policy as a tool for macroeconomic stabilization under this plan in its purest form? Given all the recent talk about using fiscal policy (here, here) to fight off the almost certain recession now facing the U.S. economy, I would think someone out there would have explored this question.
Bruce Bartlett (abbreviated version)
Fair Tax Official Page
NY Times Piece
Fair Tax Wikipedia
Fair Tax Blog
Tax Foundation (Article Round Up)