PIC 18F4550 microcontroller is equipped with USB peripheral that allows to get rid of USB-to-TTL level converter circuits like FT232RL. This saves board space and money. Anyway lots of gets scared of USB complexity and avoid using native USB. Well this is true unless your starting point is a working project template.
Gaurav have put up a working project example that utilizes PIC’s USB as HID device that is automatically recognized and installed by most operating systems like MS Windows or Linux. His project allows controlling 16 I/O pins of microcontroller by clicking buttons on PC screen. This may be a good starting point for your next USB based project.