PHP Code:
<?php
$file = "bannerlist.txt";
$banners = file($file);
srand((float) microtime() * 1235689);
$selected = array_rand($banners);
$SelBanner = trim($banners[$selected]);
if ($SelBannerhahahaha"") {
$SelBanner = trim($banners[0]);
};
echo $SelBanner;
?>
This will pull a single line from the file "bannerlist.txt" and place it where the php code is located in your site.
So just make each line of the text file, an image or href tag and your all set.