With nicolas we started to have a look at the eclipse-php-parser (provide with PDT), to export a famix-mse file from a PHP project. We already started to build an eclipse plugin that does some work:
=> We create an AST for each php file of the project
=> Then we have a visitor on this ast, and we are therfore able to make a specific action for each kind of node visited
=> For now, we just export some FAMIXNamespace, FAMIXClass, FAMIXMethods.
So  what's left is to  implement each visit-method to extract informations for each node visited. For that we will have to know a bit more PHP :) Maybe the metamodel will have to be extended to take into account some PHP-specific elements, I don't know.
If you want to have a look, sources are available via svn at:
Vervaine provide the extractor (not yet finished) for Java ans this one for PHP. Both are using a common mechanism to generate famix entities and extract them to mse.
I will be on holidays until august and will probably no longer work on it until august. So if you want to have a look (and have the courage to install eclipse to read java code:)), have some suggestions, want to implement something, feel free to participate :)