How do I get started in Amiga Game Development on an emulator?

[ElPolloDiabl]

There is Amiga E.
Google for it and and you will get some links.
Also check this page: http://www.amigacoding.com/index.php/Main_Page

You did say Game development so one of the game packages might be a good start to get something going quickly.

If you go for 68k assembler or C you will want the ROM kernel manuals.