Help with Mail()

From:	James Angelo Aves	Date:	Wed, 20 Jan 2010 01:57:26 +0000
Subject:	Help with Mail()
Groups:	php.webmaster
Request:	Send a blank email to php-webmaster+get-7089@lists.php.net to get a copy of this message

I have php 5.3.0 and 5.3.1 installed, could you tell me the step by step procedure so that I can use mail() function, on a older version, I can easily send emails, but now it seems that i cannot... This is what appears in sendmail.log Jan 15 16:03:17 host=localhost tls=off auth=off from=james_03_aves@yahoo.com recipients=james_03_aves@yahoo.com errormsg='cannot connect to localhost, port 25: Unknown error' exitcode=EX_TEMPFAIL Thanks...