Just posted a tutorial about tables in Code Exchange because I was just using this functionality in my game and figured other people could take advantage of it too:
http://developer.anscamobile.com/code/tables-lua-dictionaries-and-arrays

Basically, I go over how to use tables in Lua as dictionaries (aka hash tables, aka associative arrays.) Most people understand how to use Lua tables like arrays in other programming languages, but tables can also be used like dictionaries which is a very powerful concept.

jhocking, thanks for that. I'm just getting my head around the API and your tutorial looks helpful. :D