How many threads/cores Postgres can utilise?

Dears,

Sorry to be a royal pain, but I cannot find it anywhere in the
documentation: how many threads/CPU cores Postgres v. 8.4 can utilise?
We're thinking about installing Postgres on a virtual machine (RedHat 5
64-bits), however not sure how many CPUs can be wisely assigned, without
wasting of resources. Can Postgres utilise multi-core/multi-threaded
architecture in a reasonably extent?

Cheers, Pete

This email (and attachments) are confidential and intended for the addressee(s) only. If you are not the intended recipient please notify the sender,
delete any copies and do not take action in reliance on it. Any views expressed are the author's and do not represent those of IOP, except where specifically
stated. IOP takes reasonable precautions to protect against viruses but accepts no responsibility for loss or damage arising from virus infection.
For the protection of IOP's systems and staff emails are scanned automatically.”

Institute of Physics Registered in England under Registration No 293851
Registered Office: 76/78 Portland Place, London W1B 1NT