Depending on where you stay, you may need to get something called a "trifacicos" or something like this. It's an adapter to go from a three-pronged plug to a two-pronged outlet. The better hotels will lend you the adapter upon request, or will have the three-pronged outlets.

Also, although Mexico runs on the same voltage, the number of cycles of their electric grid is slightly off, which can lead to mild overheating when you draw lots of power (v.g. recharging your laptop).