How do I call up data from multiple excel files into one constantly updated file?

EDIT: I think this question belongs over at superuser not here at Stackexchange.

What I would like to do is have a single excel file that calls up data from every excel file in a given directory. Specifically if I have a time sheet excel file from multiple people working multiple different job numbers I would like to have that data populated in a single file for everyones times. The directory where the files are stored would be updated weekly so I would want the "master" excel file to reflect the weekly changes automatically...hopefully. Is there an easy way to do this that I would be able to teach someone else?