http://zoo.cs.yale.edu/classes/cs490/05-06b/brown.grober.savvides.pdf
Each device on the USB is identified by a Vendor ID and a Product ID; VID & PID. VID
numbers are managed by USB-IF and each number is licensed to a specific vendor; no two
VID numbers are used by more than one vendor. On the other hand, the PID is used by the
vendor to distinguish vendor products and is assigned without regard of other vendor PIDs.
These numbers together constitute a unique key that identifies devices on the bus which the
operating system uses during communication.
Every USB peripheral is required to implement one or more device descriptors that include
information about the device class (type) and its capabilities; Endpoints and communication
configurations. The host will request descriptor(s) during the enumeration process, which it
will use to register the device with the operating system using the VID and PID, load the
appropriate drivers, and set the rules of communication. A detailed UML diagram of the
enumeration process can be found in Appendix A.
UBW (USB Bit Whacker
http://greta.dhs.org/UBW/
If you want to change the VID/PID you have to change it in two files, in the mchpcdc.inf file for windows and in the usbdsc.c file for the pic. The VID and the PID must match in both files.
http://www.picbasic.co.uk/forum/archive/index.php/t-6457.html
FAQ on the topic of VID/PID
http://www.dlpdesign.com/usb-prev/vid.shtml
Introduction to Embedded USB Development
http://degood.org/tcf2006.pdf
Migrate Your Serial Application To USB The Easy Way
http://www.cin.ufpe.br/~acb/Mecaf/USB/www_elecdesign_com_Articles_Print_cfm_ArticleID=10957.pdf