Microchip is now offering a free Graphics LCD library for use
with PIC24/dsPIC/PIC32. It also has support from 3rd parties
like Segger and Ramtex.
Segger has emWin which is very powerful but not cheap.
Ramtex has the Font Editor and Graphic libraries for popular LCDs.
They have GLCD simulator as well. They are one of the partner for
Microchip's Graphic Library.
This Chinese guy has a nice software called LCD Font Maker which
only cost US$. It supports many languages including Chinese.
Atmel has the free LCD editor and LCD plug-in for AVRstudio.
Pocket MicroTechnics has the GLCD Font Creator and plugins
for SawFish/Proton Basic compiler and MikroElektronika
This website has a free GLCD font generator which exports
to C compilers like WinAVR and Codevision or similar.
This website has free Simulator for LCDs.
lcdproc is a nice project for Linux/BSDs.
There are also many examples on the internet about using
LCDs, Graphics LCDs, OLED displays with Microcontrollers.