Search the Forum for Pickit2 clone or Pickit2 lite. You'll find ample results with schematics, and layouts. You may use google too. And Pickit2 clone works on Windows Vista and 7 too.
Here is the schematic, PCB layout and codes required to make a PIckit2 clone
i made usb pic programmer from open source but its not working well, can you plz tell me if you buit one what were your results.......because when i connect it comp. shows unrecognized device error