I use this utility to convert files in Apple monitor format files to AIFF. Once in AIFF format I can download them to a real Apple II using a portable music player (iPod) and the cassette port on a real Apple II. This is the easiest and fastest way I know of, to move files to real Apple II and is an essential part of the cross development process I use for developing Apple II programs.
This version has only been tested on Intel MAC, but it was converted from a Mac PPC program, fixing endian and word length issues, so it may work, as is, on other platforms. I have a similar version for Apple 1, but it hasn’t yet been converted to Intel Mac. Here is the source for the Apple2 monitor to AIFF program.