mail()

Hello all, I am using the following code but when I view the sent e-mail (in my yahoo account) the link info is all plain text. I see the <a tag and everything. How do I create it as a link? I know I can send them because I have done it before in my yahoo e-mail, just never through php and mail(). Thanks, Eddie $mailcontent="Thank you for registering with AirCharterUnited \n" ."Your Username is $uname and your password is $pword \n" ."Please click the following link to activate your account \n" ."<a href='http:\\www.aircharterunited.com\pages\activate_account.php?clientid=$u name'>Activate Account</a>"; mail($email,'Thanks',$mailcontent,"From: aircharterunited.com");