Scripting TutorialsLink - DiegoIsAwesome's XSE Scripting tutorial. Very beginner friendly
Link - Old school scripting method but still somewhat beginner. By Foullump
Link - XSE tutorial by Raikou-kun.
Mapping TutorialsLink - Haefele's AMap mapping naturally tutorial.
Link - Link's mapping tutorial.
Link - Neti's mapping tutorial, very simple and starts off a lot of great mappers.
Link - Ray's mapping 'secrets'.
Link - Block editing in Amap.
Graphics TutorialsLink - 240/256 color titlescreen tutorial.
Link - tile inserting the 'easy' way.
Link - Guide to adding DPP sprites to GBA roms...
Link - Worldmap hacking, a bit more advanced.
Others will be added at another, stick with these basics to get started though...