Snap Preview Anywhere™

What is Snap Preview Anywhere? Snap Preview Anywhere enables anyone visiting your site to get a glimpse of what other sites you're linking to, without having to leave your site. By rolling over any link, the user gets a visual preview of the site without having to go there, thus eliminating wasted "trips" to linked sites.

Snap Preview Anywhere is a tool for site owners to provide a sticky and informative experience for your users. And it's free!
http://www.snap.com/about/spa1A.php