If you want to use PHP for public / private key encryption jobs without needing to know the ins and outs of the Open SSL extension, the following may be of interest:
http://www.karenandalex.com/php_stuff/_class_OpenSSL.phps
This class was unavailable for a long while (server problems) but is now back up. Apologies to those who clicked through and got a 404
I hope it is useful to you...
Alex