Here's some good reading on stuttering and how it relates to Tourette Syndrome.

While I've also heard reference to stuttering tics, stuttering is not generally considered to be a tic, although the two conditions are frequently seen together. There are some types of tics that could be mistaken for stuttering, like echolalia/palilalia, which involve the repeating of certain sounds, words or parts of words. Because of the nature of Tourette's, anything can be a tic, but it seems more likely that one would have both conditions instead of one condition mimicking the other.