It depends on what language you are interested in.
If you are interested in 'C' or 'C++' the RKM manuals
are a must and just about any beginners books, if thats
what you are. Then join a Yahoo support group.
But if you're interested in basic there's AMOS not too
many books out on Amos but its well supported in the
Yahoo groups. There's also AmiBlitz, also not many books
out on AmiBlitz (formerly Blitz Basic).
Then there's ACE Basic (a compiling version of AmigaBasic)
Ace Basic is my choice, I ignore all the Bad-Mouthing
AmigaBasic gets, its better then you are led to beleave.
Lots of books around on AmigaBasic.
Mel