PHP mail function doesn't send email

I set put display_errors on, and made a test page with just php mail function, sending to my gmail account. No errors appear, but the email does not get sent. OS: CentOS 4.5 . I need to be able to send emails from PHP somehow ASAP, please help.

 

I added a mail funtion to one of my pages some days ago!

I know that you can use the mail from PHP, but have a look at XPertMailer!
It's really a nice PHP class to send TRUE emails with PHP.

And.. It's so easy to use..

More info @ http://www.xpertmailer.com

 

I don't have PHP5.

 

Get the PHP4 version

 

PHP Version 4.3.9

 

Any errors in your mail log?
Also, please make sure your server isn't blacklisted: http://www.mxtoolbox.com/blacklists.aspx