Back in 2004, PHP was named number one language of 2004. Since then, it's hovered in the top ten, maintaining its popularity and ranking, including a move up from 5th place to 4th (as mentioned on the Zend Developer Zone).
The TIOBE Programming Community Index has been updated for April 2006 showing their view on the status of programming languages in the development community. PHP moves up a spot from 5th to 4th. The long-in-the-tooth C fades back a bit relinquishing 1st place to Java, while C++ gains on its brethren with PHP biting on its heels (a margin of 0.02 between their percentages). PHP has a higher climb rate so expect another big move in the coming year.
For those that are wondering "why should I care?" about this random index? The post mentions how they come up with their numbers. It's mainly a popularity contest, but it's useful for seeing which way the public sways. The post also mentions thatm while it's one way to check the popularity, slightly altering the search parameters can give dramatically different results.