One of the best USB and/or Serial multi-pic programmer is here:
http://siscobf.webcindario.com/winpic800.htm
Schematic, .hex, drivers and software as included. And completely FREE.
Support 16Fxxx, 18Fxxxx, 24xxxx and dsPics family.
The soft is in constantly updated.
NO need for a USB converter it is done in the microcontroller.
same for power supply converter from 5vdc to 13.6vdc