First you need a way of transfering the .adf files to the A500. Either through a nullmodem cable, as said before. Easiest is with CrossDOS, although some won't fit on a DD disk. a high density drive would be a better bet (you can fit all files on HD floppy's).
Then on the Amiga you need a tool called ADF Blitzer, this asks you for an input file and writes it back to floppy.
Having a A590 (or any other SCSI controller) is the easiest way, and the way I do it. Get yourself a nice external SCSI CD-Rom drive, bang 640MB of ADF files on a CD and off you go!
