All three major search engines provide webmaster tools that give you detailed information and statistics about how they see and crawl your website. In order to access most of the features, you will have to verify your sites. Here are links to each service and examples of each ones META tags.
Example: <meta name=’google-site-verification’ content=’dBw5CvburAxi537Rp9qi5uG2174Vb6JwHwIRwPSLIK8‘>
Example: <meta name=’y_key’ content=’3236dee82aabe064‘>
Example: <meta name=’msvalidate.01′ content=’12C1203B5086AECE94EB3A3D9830B2E‘>