I have used Lua (Lua 4.0) as a data definition language in two projects on both PC/Windows and PocketPC 2002.
I'm using Lua 5.0 for data definition and scripting in a project I'm currently working on under Windows.
Here is my first tutorial:
Here is a page with some ideas and techniques for script security:
Tutorial on lua threads
A HUGE thanks to the authors of Lua for their great work and dedication.