Economist Tyler Cowen isn't exactly an early-bird to the party, but he makes the case against free parking in a New York Times column:
Is this a serious economic issue? In fact, it’s a classic tale of how subsidies, use restrictions, and price controls can steer an economy in wrong directions. Car owners may not want to hear this, but we have way too much free parking.
Matt Yglesias had a different take on the problem, comparing free and underpriced parking to Soviet-style price controls:
People generally understand that there were shortages and long lines for things in the Soviet Union because goods weren’t priced according to supply and demand. And people generally understand that, in general, price controls will tend to lead to either gluts or shortages. And yet few people understand that this same principle applies to on-street parking. In many places, it’s hard to find and that’s because it’s not priced properly.
More food for thought.