mail() function doesn't work...

[MSwanson]

My mail() function doesn't seem to work on Windows Server 2003. 

I've tried to test it with:

[code]
<?php

mail('[email protected]', 'Test Subject', 'Test Message');

?>
[/code]

But I don't ever get the message.

php.ini:

[code]
[mail function]
; For Win32 only.
SMTP = localhost ; for Win32 only
smtp_port = 25
sendmail_from= [email protected] ; for Win32 only

; For Win32 only.
;sendmail_from = [email protected]

; For Unix only.  You may supply arguments as well (default: "sendmail -t -i").
;sendmail_path =
[/code]

I'm also running Exchange 2003.

Any suggestions?