I'm not sure exactly how many of my readers are webmasters, but as far as i can see the poll in the sidebar is going seems that many of you have websites. I'm wondering that because i have something to give you, but you can use it only if you have a website.
I've created a wordpress plugin that adds a tool to your website where your users can lookup any IP address. So if you have a wordpress based website, you can download the plugin , upload ipgp directory to wp-content/plugins/ , then go to admin panel and activate the plugin.
From now, you have to option, if you have widgetized sidebar, you can go to Appearance -> Widgets and simply drag and drop the Ip address lookup widget to the sidebar. If you want it to be displayed elsewhere, just edit the template file where you want to add it and paste the following code: <?php showIpLookup(); ?>
You visitors will appreciate this feature.