How to Control the Persistence of A PostgreSQL Connection

Have been reading the manual and searching for connection timeout
information, but
I don't think what I have found answers my questions. Most of what I found
so far
is C library functions in Chapter 27 on version 8.0 manual (am not a C
programmer).

I saw connection timeout discussed a little bit with login / authentication
type
parameters, but it had to do with getting in, not maintaining a connection.

We are connecting to PostgreSQL using clients running JBOSS. What I want to
know is:
- from the PostgreSQL side, how long will a connection to the database be
kept open
if inactive for a period of time, and where are the parameter(s) to
affect that?
- does PostgreSQL do connection pooling?
- is there any way I can tell if I am getting into trouble on the number
of
connections open, and how long they have been open, outside of user
complaints
of lack of service (unable to connect)?

I am on Windows 2003, using version 8.0.