Howdy,
Hmm, that’s a fine question!
I’ll offer that Ubuntu and Debian include Suhosin built into PHP by default… but that’s not really helpful to getting you up and running on CentOS 
So how would you get it working on CentOS?
Well, the first key is that you’d probably want a version of the module compiled to use the PHP version within your existing distro, rather than their own custom PHP version.
The EPEL repo is good about that sort of thing… you may want to take a peek at this php-suhosin version here:
http://pkgs.org/centos-6-rhel-6/epel-i386/php-suhosin-0.9.29-2.el6.i686.rpm.html
If you download that .rpm, and then run “rpm -ivh” on it as root, it should (in theory) install cleanly onto your system.
Let us know if that does the trick for you!
-Eric