You should be able to telnet to the port and get a response back as in the exmple below.
Of course substitude the ip for the database.
[postgres@pgprd01 londiste]$ telnet 127.0.0.1 5432
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
> Date: Mon, 1 Feb 2010 09:13:34 -0800
> From: adrian.klaver@gmail.com
> To: christine@ingenioussoftware.com
> CC: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Connect to Postgres problems
>
> On 02/01/2010 09:10 AM, Christine Penner wrote:
> > I have re started the computer (a few times) since I did all that.
> >
> > Christine
> >
> >
>
> What is the error that you are seeing on the client and in the logs?
>
>
> --
> Adrian Klaver
> adrian.klaver@gmail.com
>
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All your Hotmail contacts on your phone.
Try it now.