Usage Stats for January 2013

PHP: 244M sites, 2.1M IP addresses

Source: Netcraft



w3techs.com provides statistics for server-side programming languages where you can also see the market share by version.

See their FAQ and technologies page for the details of the methodologies used for the surveys.

You can also see how popular PHP is relative to other Apache modules at SecuritySpace's Web Survey.

There is also a Programming Community Index provided by TIOBE.