mod_proxy_fcgi, which is newly available in Apache 2.4, is just for this type of use case. The Apache wiki entry for PHP-FPM has some good guidance to get started.
mod_proxy_fcgi documentation also includes specific examples for setting up PHP-FPM and the PHP documentation also has helpful information.
Note also (notwithstanding some erroneous references to the contrary), unix sockets are not available for this until Apache 2.4.10 (2.4.9 was not really released), so you can't use them under 2.4.7.
On the other hand,
mod_fastcgi is notoriously difficult to set up and a memory hog. Additionally,
mod_fcgi doesn’t support spawned CGI servers. Because PHP-FPM is managed by itself, not by Apache,
mod_fcgi isn’t the best choice.