psqsl -> remote db

I'm sorry, I'm sure I should be asking this someplace more general, but
apparantly the word 'port' is used in so many different contexts that a
google search turns up fruitless ;)

I'm just trying to access a remote postgresql database on port 5432,
which does not appear to be open on the remote computer.  I'm on a
MacOSX and  cannot figure out for the life of me how to open up this
port on the computer.

This is probably a unix question if anything, but any help would be
apprecaited.

-Andrew