Parallel interfacing LCD with MCU at least need 6 I/O pins (4 bit mode) and maximun can up to 11 I/O pins (8 bit mode). The I/O pin can be cut down to 3 pin by serial iterfacing using shift register. They were few shift register can be used such as 74HC164, 74HC595, CD4094 and any compatible 8 bit shift register. Before you attempt to do serial interfacing, it is good pratice to familiar with parallel interfacing. You can find many reference from internet.Following diagram show the serial interfacing Hitachi compatible 2 X 16 LCD modules with Pic16F84 or Pic16F628 MCU.
Download documentation and source code for serial interfacing LCD with PIC here (zip file)