Off topic php / mysql forum registration help!

[lektr0nikz]

Hi! I know this is off topic from irc, but i tried going to php forums and noone would help me! Maby you guys would know whats wrong:

I just installed wbb forums on my own server (windows xp running apache and mysql 4) and i installed the forums perfectally (woltlab burning boar forums, note: this is same problem with any forums), but when my friends try to register they get this message ! (when anyone trys to register) And it dosent email them anything, (so pretty much they CANT register for my forums!

Warning: mail(): Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set() in F:\xampp\htdocs\vizion\bb\register.php on line 69

What do i have to do to fix this problem?! What is my SMTP stuff? THanks lot !

Do i need to set up a mailserver? if so please explain! (im using the xaamp php/mysql setup so it comes with alot of programs!)