Wikipedia actually has a pretty good (though brief) discussion of this. They mention three alternative strategies that could deal with noise: tit for two tats (only defect after your opponent defects twice), tit for tat with forgiveness (randomly cooperate after an opponent's defection with probability p), and contrite tit for tat (cooperate extra after you accidentally defect). The article that they cite for contrite tit for tat, Boyd (1989), looks promising. And googling contrite tit for tat turned up a relevant paper by Wu & Axelrod (1995) (pdf):

Noise, in the form of random errors in implementing a choice, is a common problem in real world interactions. Recent research has identified three approaches to coping with noise: adding generosity to a reciprocating strategy; adding contrition to a reciprocating strategy; and using an entirely different strategy, Pavlov, based on the idea of switching choice whenever the previous payoff was low. Tournament studies, ecological simulation, and theoretical analysis demonstrate: (1) A generous version of Tit for Tat is a highly effective strategy when the players it meets have not adapted to noise. (2) If the other players have adapted to noise, a contrite version of Tit for Tat is even more effective at quickly restoring mutual cooperation without the risk of exploitation. (3) Pavlov is not robust.

Boyd, R. (1989). Mistakes Allow Evolutionary Stability in the Repeated Prisoner's Dilemma Game. Journal of Theoretical Biology, 136 (1): 47-56.
Wu, J. & Axelrod, R. (1995). How to cope with noise in the iterated prisoner's dilemma. Journal of Conflict Resolution, 39, 183-189.