<?php
//get the current $user object to determine the logged in user's id
global $user;

//now load the user id from the profile page into another object by pulling it from path
$usertmp = user_load(array('uid' => arg(1)));

if ($user->uid == $usertmp->uid) {
     //we're on the logged in user's page
     print "<h2>You haven't created any blog entries.</h2>";
     print "<h4>You can create a ";
     print l("new one.","add/blog");
} else {
     print "<h2>".$usertmp->name." hasn't created any blog entries.</h2>";
}
?>