need some help programming a pic

I have some hardware that has a PIC18F6680 pic cpu. This is older hardware that is non programmable that we are starting to replace with a reprogrammable version. The newer version is the basically the same, but has a maxium max3233e rs232 chip, and a mini headphone jack that we connect to a laptop to program with vendor software via a laptop w/serial port. What would be the easiest way to reprogram these older pic chips? I was thinking maybe making a board with a power supply and that rs232 chip on it and temporally solder leads to the chip? Or possibly un-soldering the chip from one unit and soldering it into the new unit, reprogram, and soldering it back into the old unit???? I can provide pics of the boards if anyone is interested..... maybe someone could offer a reprogramming service if i provide the software? Thanks.