My personal experience is just to use Maptool personaly. Here's are three categories of video tutorial's for it to learn the basics.
MapTool : Overview
Tutorials : Step by Step
Tutorials : Beyond the Basics

Aside from that, I personally don't think distributing a VTT ready file is the best method. You would need to set it up for each application out there because they all have their own proprietary file format from my understanding. Up to you on where you wanna go with this and good luck!