I'm just back online after a successful LinuxWorld at Boston. Oracle had an exhibition hall booth dedicated to PHP, a couple of exhibition hall short presentations on PHP, and ran an InstallFest showing how to install and use PHP and Oracle Database.
People who'd been at Boston in 2005 said the conference was less busy this year. The presumption is that Linux is maturing and doesn't need lots of buzz. For me, it was still busier than some specialized conferences.
PHP feedback was great and I spoke with long-term, new, and potential Oracle customers using PHP. Momentum is obviously building.
Coupled with the free version of Oracle - the Oracle10g Express Edition database (which won the Best Database Solution at the conference), PHP is certainly highly usable.
The InstallFest documentation abbreviated from our Sydney opus is at OTN's PHP Developer Center (We're still enhancing the full version for future publication).
Some photos are on Flickr