Norm Ornstein has written this Roll Call oped (free access). Norm concludes:

I do not think, in principle, that requiring a photo ID is evil or onerous. An official photo ID can protect voters against charges that they are ineligible to vote. I agree with civil rights activist Andrew Young that a photo ID would be a huge help to poor people who are often victimized by huge fees they are charged to cash paychecks because they lack any such identification.
But there are certain clear principles that need to be applied. Any such ID has to be offered for free–including no-cost access to whatever support documents are required. In a free society, no one should have to pay to vote, and there should not be any unequal burden on those citizens who want to vote. Not only should the ID be free, but it must be readily accessible–in multiple places convenient to the poor and elderly, and through mobile vans to reach those who can’t get out easily to the fixed sites.
With these conditions, a voter ID is not an undue burden. But to get to that point requires two things: federal guidelines for the states, under Congress’ constitutional power to regulate federal elections, and federal money to make the system work for all. This issue is significant and controversial enough that it ought to be on Congress’ agenda this year. But Congress’ track record on election reform this year suggests that the chance of that happening is zero.