SAMP-Manager is a project mainly written in C++ and C, it's free.
Server Manager for GTA San Andreas Multiplayer
This is a Tool to control multiple GTA San Andreas Multiplayer Servers. It is writen in C++ with Qt and there is also some AutoIt and Shell.
To compile from source you need the QT-SDK.
On Windows you need AutoIt, too.
The Server is tested on Windows and Debian Lenny. The Client is tested on Windows.