Php 5.3 is not available on Project Web platformSourceforge is one of the biggest hosting platforms for open source projects.
Php 5.3 is required by the Doctrine 2 ORM and will be probably required for Zend Framework 2.0; php projects should be able to develop for 5.3 without losing the availability of the project web platform for testing and demos.
The Project web platform is the web hosting space available for every project at http://PROJECTNAME.sourceforge.net, which can store sample instances of web applications, such as public demos or development checkouts.
This platform provides a mysql database and php 5.2, but I think it's important to help open source projects adopting php 5.3 and its shiny new features, like namespaces and closures, whilst keeping example deployments on the sourceforge.net servers.
If you also think php 5.3 would be a useful option on Sourceforge web hosting, vote for the solution or propose new ones on the IdeaTorrent. :)
The Practical Php Patterns series will resume on next Monday.