Hi,
For this you need to create an software UART in PIC16f877A, which is making two pins of Pic to act as a rx and tx using coding.This can be done by many ways, one of the easiest way is to use Mikroc compiler for PIC which has inbuilt software UART library. You can also do this in Mplab and Hi Tech c compiler, do search for mplab codings you can get idea about that.