Configuration Parameters

I am setting up a web-based app on Apache, GnuJSP and PostgreSQL 7.0
running on freeBSD. Occasionally I get a "Too many clients" exception. If I
expect about 50 concurrent full-time users, what are appropriate -N and -B
values for the postmaster? What would be appropriate values for SHMMAX,
SEMMNS, SEMMNI, NPROC, MAXUPRC, NFILE and NINODE? Are there any other
configuration parameters that I need to worry about?

Thanks in advance,

Richard Ehrlich