Grab this first (I'm assuming your on PC??)
Emu
Then grab this, "Amiga In A Box", its basically a front end for the WINUAE emulator, its great.literally puts an Amiga into your pc, hard drive, the works.
Frontend
just go to the download area and grab the aiab-20050606.zip file.
More info here-
AIAB INFO
You will need the amiga kickstart roms to get it started, you can get them from here, read the disclaimer of course
kickstart