Most of the info I needed for my 1st WoW AddOn I found at wowwiki.
Sounds from what you describe like we have simular programming exp, most of my expierance has been in VB though.
I opted to create the basic interface in XML, and use the LUA to do the work and updates to the interface. Learning how Blizzard implamented XML was the biggest challenge for me, know/knew basic XML prior. But part of my objective was to NOT use any of the librarys and such out there, as I HATE those extra dependancies that can break my stuff when those authors update on a whim.
Usefull info/tutorials found at the following URL's
http://www.wowwiki.com/Category:Interface_customization
http://www.wowwiki.com/Category:HOWTOs
http://www.wowwiki.com/World_of_Warcraft_API
http://www.wowwiki.com/Widget_API
http://www.wowwiki.com/Lua_functions
http://www.wowwiki.com/Events_%28API%29
Following might be usefull too:
http://www.wowwiki.com/Global_functions
My top Favorites (have been most useful) as my project has progressed
http://www.wowwiki.com/World_of_Warcraft_API
http://www.wowwiki.com/Widget_API
http://www.wowwiki.com/Lua_functions
Some Tutorials I have found that could be usefull
http://www.tentonhammer.com/node/26414
Good luck,
Henry
aka Del