Programming
Well, there are several suggestions that I might make.
1) If you are used to programming 64's or other non/OS Microprocessors,
forget everything you used to know.
2) Unlike other micros, the Amiga has a real operating system with well
defined operating system interfaces. Plan on using these interfaces to
the hilt if you want the greatest level of compatibility.
3) Be prepared for an initial steep learning curve because of the above two
items.
Now, with that out of the way, you seriously want to get the Rom Kernel
Manuals from Addison Wesley. They cover all the system interfaces and give
you some overview of what the system is like. You will also want to get the
latest AmigaDos technical reference manual from Bantam books. These make up
the official Amiga programming documentation. The other big thing to
consider is C, despite other languages available on the Amiga, C is the
standard (and official) programming language for accessing the system
interfaces.
Feel free to ask questions here, there is a large base of system knowledge
online and we can handle just about any programming question that you can
throw out.