Feild Pic programing

I am looking to make a pic programmer. Basicly i need a programmer like MeLabs Field programmer, i.e a hex file on an SD card that will program a Pic without being at a computer. The Melabs Field Programmer does almost exactlt what i want to do except i need to give the Pic a "Serial number" just like you can do with the "U2" programmer, this function is not supported by the Feild Programmer. So looks like i will need to build my own. Problem is i have never looked at "Programming" a Pic before - thats why you buy programmers. I have had a look at the datasheet for programming the appropriate pic, but seems it would be a bit of a challenge, does any one have code samples to get me started? Or even some simplified info for programming a Pic.