This plugin will allow you to easily verify your WordPress website with Google Webmaster Tools, Bing Webmaster Tools and Yahoo! SiteExplorer.
Download the plugin, extract and upload it to your plugins folder on your server.
Activate the plugin.
Go to Settings, and Easy Verification.
Go to Google Webmaster Tools and Yahoo! SiteExplorer to get your verification/authentication information.
Enter the meta value on the Easy Verification page and Save Changes.
The plugin will generate meta tags on the homepage of your website.