Sure -- just as if it were a .ppt file. In fact, if you want, just rename it
to .ppt. Otherwise, find it in My Computer or in Windows Explorer,
right-click it, and choose Open, Edit, or Open With from the Context menu
(depending upon certain configuration factors).
The key thing to remember is this: There is absolutely no difference at all
between a .pps file and a .ppt file, except for that one letter in the
extension. The .pps designation tells PowerPoint to bypass opening it for
editing and go directly to show.