FLListServer is a full-fledged, custom-built list server akin to the official Microsoft list server (which was shutdown) which reenables the Multiplayer server list of Microsoft's Freelancer.
In short, it acts and behaves exactly like the original GLS and provides the same functionalities.
It works both client-side and server-side.
In order to install it, you must browse to your Freelancer executable folder, usually found under C:\Program Files\Microsoft Games\Freelancer\EXE. From there, locate "Freelancer.ini" and open it up in a plain-text editor.
You'll find the following line:

hostname = ; GUN server in Redmond (DNS entry)

Replace that line with the following lines:

;hostname = ; GUN server in Redmond (DNS entry)
hostname = ;

Alternative download:

Freelancer List Server Patch (installer)
Freelancer List Server Patch as flmod file
Listing Freelancer servers since 2008