PluralEyes for Media Composer is an application which automatically synchronizes clips in a sequence. In Media Composer, you have to create a sequence and add the clips to it, then export the sequence to AAF. In the PluralEyes main window, click the Open button and choose the AAF file that you exported earlier.
PluralEyes will create an output AAF file and will tell you where it is. In Media Composer, import that AAF file. The result will be a copy of the input sequence but with the clips moved around to be in sync.