The TIOBE Programming Community index tracks the popularity of various programming languages. The index is updated once in a month. The ratings are based on the world-wide availability of skilled engineers, courses and third party vendors. The popular search engines Google, MSN, and Yahoo! are used to calculate the ratings.

For example the PHP has moved up a spot to 4th in the ratings in the month of october

Where PHP stands currently

Position (Oct 2006): 4
Position (Oct 2005): 4
Ratings (Oct 2006): 9.863%
Delta (Oct 2005): +0.19%
Status: A

The status ‘A’ means it is a mainstream programming language language.

The full list can be found here: http://www.tiobe.com/tpci.htm

Some more interesting facts about that list: Java, C, and C++ makeup the number 1,2 and 3 respectively. F#, a Beta microsoft programming language also made it to the list at number 56.

The first official beta of F#, Microsoft’s programming language has been released 3 months ago. This variant of C# with many functional aspects is already at positioned at number 56 of the TIOBE index.