Somehow this happened so quietly that I missed it a couple days ago!
PHP 5.3 has hit release candidate 1. (download)

This is exciting because it’s going to be a “free” 15%-20% performance boost over 5.2 for many programs like WordPress and bbPress. It’s the version I am waiting for to finally replace PHP 4.4

What’s new in 5.3 [PDF] http://ilia.ws/files/phpquebec_php53.pdf