php-msrpc is a PHP binding for MSRPC, which is Microsoft's proprietary protocol for managing Windows servers and the like. It uses the libraries provided by the Samba-TNG project, which is required for use. php-msrpc will enable you to write Web-based administration tools for Windows (such as a user manager) with a Web server running under Linux.
SAPRFC is the extension module for PHP that allows you to call ABAP functions in an SAP R/3 system from PHP scripts. It is also possible to write an RFC server program in PHP, and call PHP functions from ABAP. Other features include using the RFC (Remote Function Call) API to make a call, discovering the interface of a function module, and mapping all RFC types to PHP strings (delivered with a test script that has a similar function to the "Single Test" option in the SE37 transaction).
Suhosin is an advanced protection system for PHP installations. It was designed to protect servers and users from known and unknown flaws in PHP applications and the PHP core. Suhosin comes in two independent parts that can be used separately or in combination. The first part is a small patch against the PHP core that implements a few low-level protections against buffer overflows or format string vulnerabilities. The second part is a powerful PHP extension that implements all the other protections. Suhosin is binary compatible with plain PHP installations.