PostgresSQL 7.x Oracle8 Comparison

I've been given the task of developing a RDBMS to handle a high-volume
of queries.  Let me begin by telling you that databases really are not
my thing, so I'm basically starting from scratch (previous experience
includes developing a low-volume Oracle system for an educational
envrionment).  My "previous experience" is why I've been given the
task.

Currently, my solution is to develop a system based on Red Hat 7.1
using the Red Hat PostgreSQL 7.1 solution.  My only constraint is
money.  And I'm trying to put this together way under budget (hence my
reasoning for giving PostgreSQL 7.1 serious consideration).

If anyone could direct me to a comparsion site, so I can evaluate
other options, or give me some advise, it would be most appreciated.

Thanks for the help.

Nick