The serial GLCD can be used with any MCU (including the PIC184550) that can output serial data. You do not need a GLCD library as it is an intelligent display that has an AtmelAVR MCU on board - you could say that the library lives in the AVR.

I do not provide sample code. You send simple ASCII codes using SEROUT (or HSEROUT) at up to 115,200 baud. Take a look at the datasheet here http://www.sparkfun.com/datasheets/LCD/Monochrome/Corrected-SFE-0016-DataSheet-08884-SerialGraphicLCD-v2.pdf and and the tutorial here http://www.sparkfun.com/tutorials/120