I've been going through tutorials and help I've given on the MT boards, and found that I never had posted this here.
Multiple Archive Templates are part of MT2.0 and above and are useful for having two different ways (idea: normal and for printing) to display your individual archives, or generating a normal page of categories and a snippit to be included elsewhere with the last categories or a number of other great tools.
This link talks about how to set them up and name them in a useful way inside of Movable Type: using archive templates – multiple, how to implement!