RPM of finale version of PHP 5.4.1 are available for Fedora in the remi repository and for Enterprise Linux (RHEL/CentOS) in the remi-test repository . This version will be really soon in the official updates for fedora 17 (after the testing stage).
Read the announcement: PHP 5.3.11 And PHP 5.4.1 Released!
This is a Fedora 17 feature.
Use YUM to install :
yum --enablerepo=remi,remi-test update php-\*
This packages are also on the road to Fedora 17.
There are also 34 pecl extension packages available for this new version.
Documentation: Migration from PHP 5.3.x to PHP 5.4.x.
For all questions or help, please use the Forums.
I plan to keep them, for a few time, in remi-test repository for Enterprise Linux.