Sending Email using [mail function] PROBLEM

Hello all
I am making a website with a login box which requires the user to register. After they register an email will be sent to them with a link to activate their account. But the problem is, i cannot get the message to be sent to them. I have altered the php.ini to many things now, but still doesnt work!!!

Look at this:

[mail function]
; For Win32 only.
SMTP = mail.???.com <----- This is the problem

I am using AOL, so would that mean i should use mail.aol.com? I have already tried it, but get a Warning with a cannot connect......etc

WHAT IS WRONG?

Ive searched other forums and they aslo had this problem. They said you will have to download a mail server. If you cannot solve the above problem then can you please give me a link with a mail server so i can download!! thanks a lot.

-Bengaltiger-