was is the normal number of postgres.exe?

We are testing an application received from a collaborator that uses the
latest version of postgresql.  After a few minutes of use we often see a
dozen or more postgres.exe listed by the windows XP task manager.  This
is at a time when we are not doing anything with the application so
these processes are not associated with our current use of the
application. These processes are using zero cpu and between 2,500k and
3,500k of memory.  Occasionally we also see one or two postgres.exe that
are using about 50% of cpu.

On another machine that is running postgresql as a service we usually
see three or four postgresql.  Any ideas about what could be causing the
large number of postgres.exe or the cpu hogging postgres.exe?

Thanks for any ideas or leads.
-=bill