I guess it depends on what type of floor you are putting down but personally I would pull the carpet out as I suspect most others have done. There is the weight
issue of having both wood and carpet down, as well as the issue of what type of wood flooring and how it connects to itself to consider - probable best to ask a floor expert on whether or not leaving the carpet in place will do any harm. The carpet should if original be pretty simple to remove - any places glued can often be taken up with a putty knife.
Use the search function on this site - use the Google option at the very bottom of the drop down menu for best results for posts and pictures of wood floor installs.