Yet another Weighing Scale Project
You can use an instrumentation amplifier such as the INA114. If you have only a positive supply voltage, then you would want a rail-rail single supply inamp instead,  an INA333 could work. The instrumentation amplifer amplifies the difference between the two inputs and adds a reference voltage to it. Since your ADC can only handle positive voltages, but your bridge may well return a negative value, you should use a, 2.5 volt reference input. This acts as a level shifter, and lets you send the signal straight into your PIC. You should calculate gain to make sure you use as much of your ADC range as possible.