DynamicWebPages.de has a new post about the release of PHP 5.1RC1 from Zeev:

PHP5.1RC1 has been published - Zeev Suraski has released the first release Candidate for the upcoming PHP version 5.1 for testing. The main improvements for this version (Zend Engine 2) include an updated PCRE Extension, many improvements with SOAP or SPL.

You can download the source for your OS here:

• Linux - tar.gz, tar.bz2
• Windows - zip
• Win-32 PECL - zip.