SiteVerify is a free extension for Joomla 1.5.x. It's a simple Plugin that allows site administrators to add the HTML META tags needed for site verification with the three major search engines: Google, Yahoo, and Live.com.
There are a few similar plugins available that served as inspiration for this one. Here are the improvements that JoomlaFare's SiteVerify Plugin brings:
Just download, install, configure, enable, and enjoy!