USB Library
Vendor IDs (VID) and Product IDs (PID)

Every USB product line must have a unique combination of VID and PID. All firmware examples use Microchip's VID (0x04d8) and a unique PID. Prior to manufacturing and marketing a new USB product, the VID and PID need to be changed. New VID and PID numbers can be obtained by purchasing a VID from the USB Implementers Forum: 

http://www.usb.org/developers/vendor 

Alternatively, Microchip has a free VID sublicensing program. An application form for obtaining a PID (for use with Microchip’s VID: 0x04d8) from Microchip can be obtained through the following link: http://www.microchip.com/usblicensing/Default.aspx 

Once a new VID/PID combination is obtained, both the firmware and the .INF file (when applicable) will need to be updated. 

To modify the VID/PID in one of the example USB firmware projects, open the usb_descriptors.c file (found in each of the demo folders). They should appear in the table used for the USB Device Descriptor. Change both values as needed. 

To modify the VID/PID in the .INF file, open the relevant INF file and search for the “[DeviceList]” sections. There are two sections, one for 32-bit and one for 64-bit, both sections should be identical. In these sections, some text will appear with the form “USB\VID_xxxx&PID_yyyy”. Update the “xxxx” and “yyyy” sections with the new hexadecimal format VID/PID values.

MLA - USB Library Help Version : 2.16
http://www.microchip.com/mla