Hi wp100 and rajudp !
Thank you all for helping.
wp100
Let me explain more exactly what I want to do, so maybe you can advice me.
I already made a "Visual C#" program that makes connection via PARALEL PORT, the connection computer -> PIC 16f877 and vice versa. And it is OK.
What I want is to make the same connection but instead of using PARALEL PORT I want to make connection via USB. But I don't know at all how to do this. I read that the 18f4550 have a USB possibilities but I consider that even 16f877 is good enough to me. But I don't have a clue how to make that connection. A connection via paralel port is so easy. Just have to use some parallel port registers. But how to use USB.
Also I'd like to move to C, but is there any free C and also tutorial for it. I have some expiriance with C++ but not for Microcontroller programming.