A couple of URLs that may guide you further:
Microsoft Office Project Home page
Microsfot Office Project 2007: Which offering is right for you?
Briefly, Microsoft Project has two components: the desktop component
which is either Microsoft Office Project Standard or Microsoft Office
Project Professional. Both Standard and Professional are used to create
the Project files which include scheduling data, cost data, earned value
data, resource utilization data and so on. Project Managers use Project
Standard or Project Professional to create the files.
Project Server is not just a file server. It is part of the "Enterprise
Project Management Solution" offered by Microsoft.
I hope this helps. Let us know how you get along.
Visit http://project.mvps.org/ for the FAQs and additional information
about Microsoft Project