NOTE: I finally got my camera figured out so there should only be 1 or 2 blurry images. On with the Instructable!
LCDs are one of the coolest things to add to any project right now. You can use them to display things from the speed of your bike, to the amount of room being used up on your RAM. This Instructable will give you a general description on how LCDs work, and how to get started using them. The information provided here will give you enough information to even develop control circuits on any Microcontroller. LCDs are a lot simpler than you think!
Step 1: How They Work
Most LCDs have a HD44780 LCD driver in them. The HD44780 is the most common LCD driver and is very easy to connect to. A LCD with this driver typically has 14 or 16 pin, with the first being ground and the second being 5V+. This is the only LCD type I will cover today being it is so common. Very common. LCDs of this type are parallel devices. That means that 8 bits of data are sent side by side (or parallel to each other) instead of in line. This is also the way parallel printer ports work which is why it such a popular decision to connect a LCD to a parallel port. Data is sent to LCD screens in a kind of 8-bit Binary ASCII code. For example: 01000001 translates to a capital a. 01000001=A. There are special symbols too like: 11110100=the Pi sign. In the instance of HD44780 driven LCDs, the first bit of data is the 14th pin and the last bit of data is the 7th pin. Unless you haven't figured it out already, this means that building a test rig, or interfacing to a microcontroller would be very simple.