As Mike Potter mentions in his new blog entry, Flash, Flex and PHP just got a great leg up when it comes to using the combination:
Patrick Mineault, who runs the AMFPHP project, has released a new version of AMFPHP 1.9, beta 2 now. However, the real big news in his blog post was the news that there is now a C based AMF extension for PHP.
According to the test data Patrick gives, the speed jump is well worth implementing the different functionality - a 100% boost, in fact, than the standard PHP version of AMFPHP. Check out Patrick's blog for the rest of these amazing stats.