Phalanger is a PHP-Compiler for the .net framework. It can be used to run existing PHP applications on asp.net webservers with far greater performance than using PHP itself:
In contrary with PHP itself the bottleneck isn’t the execution of the code itself but the underlying functions for executing the code: phalanger still uses the PHP library for the PHP functions which creates a lot of overhead due to interop and makes the PHP objects not as native to .net as it could. In contrary to PHP you would be best off not using the functions but trying to use the .net ones or your own written.
In my own little benchmark for basic differences between normal .net and PHP, PHP came out to be 5000 times slower. When phalanger finaly compiles into proper .net code by avoiding any PHP library and PHP interop it would be a -lot- faster. When people would start to like it and install mod_mono on their apache webservers to run it they would probably find that they’ll be better of with asp.net with c# or vb.net. They after all got a way cleaner syntax than PHP and are happier working with the .net framework. (I don’t want to know what hacks they used at the phalanger compiler to get include and require working when compiling everything to one dll).
In the mean time microsoft is rubbing its hands