mmm, PIC16F877 don't provide any built-in USB support. The best you can do is to use a USB-serial adapter or a USB driver chip... don't do it, choose a PIC with a built-in USB module such as PIC18F4550.

Starter project? Why not? Have a look at this one...

USBDemo, something to learn USB a little bit
http://www.picbasic.co.uk/forum/showthread.php?t=5418&