David,

The best site on the net for Mac PIC Programmers is
http://members.aol.com/fdeck/main.html. He has a HyperCard stack which
serves as the compiler and front-end to the programmer. Included is a
circuit for the programmer and a serial connection to the Mac. The
directions are excellent. The warnings should be heeded lest you "blow-up"
your computer. A PCB, parts, and preprogrammed PIC are available from
MacSciTech. You might try contacting the author directly for a
preprogrammed PIC. He is a nice guy!

As regards Ben Wirz comments on damage to his Commodore-64 at age 13, I
have blown the RS485 on a Mac with a major brand modem that sent a power
surge into the serial port on power-up. It manifest as "rebooting" the
computer prior to actually blowing the chip. Fortunately, most Macs are
equipped with two serial ports, so the computer was not rendered completely
useless.  The point of my story is that even supposedly well engineered and
well built commercial products can kill your computer, though it is less
likely that a commercial product will damage your computer than a
home-built peripheral.

Consider building your programmer with optoisolated inputs. For info on
RS485 optoisolators see http://www.bb-elec.com/welcome.html for a complete
rundown on serial connectors/protocols and optoisolator circuits. You might
build a serial port optoisolator as your first project and use it for all
subsequent projects. Good insurance!  The other consideration is using an
old MacPlus or SE for your projects. They run HyperCard with adequate
speed, and if damaged are less expensive to replace than Mom & Dad's new
PowerPC.

Another alternative is to find an old PC-DOS machine and use that as your
programmer with David Tait's parallel port PIC programmer. Old PCs can be
found at garage sales and Goodwill/Salvation Army stores for about $30
complete with monitor.  One advantage to having an old DOS machine on hand
is that there are freeware DOS PCB design and router programs available on
the net. Several companies have posted their DOS products as freeware after
marketing Windows based packages. My sense is that hacking hardware and
software is much easier on old DOS machines than it is on the latest
Windows and Macs. There is a lot less OS garbage to get between you and
your chip!

Keep up the good work!