Ever wonder how people can "guess" your IP and show it on their site? Well, they're not guessing, it's a script. And it's a really easy and short one, too! To do it, you must be able to use PHP on your site. Anyways, just place this code where ever you want your visitors IP address to show!
<?php echo $_SERVER["REMOTE_ADDR"]; ?>
This code's neat because when people view your source to see how you got their IP address on your site, it just shows their IP, not the code.
Tutorial adapted from Sillymahala.com. I did not steal this, since I own Sillymahala AND this site.