I'm happy to say that the next instructable in the series will be the Voiceberry Pi itself! Not much longer to wait.
The HD44780 is a very common driver for LCD displays like the one shown below. Normally, the circuitry is built right into the display, and you just have to connect a ribbon or headers to your circuit. That's what I'll e covering here.
My display was purchased off eBay, and is a 40 character by 2 lines. It's a bit bulky, and has more characters than what I need for what I've got planned (that Voiceberry Pi again), but it's a great display otherwise.
One advantage of HD44780 driven displays is that there is a ton of information out there on how to use them, and even a good amount of information on how to use them with the Raspberry Pi. Because of this, I won't go into too much detail on how to run the display from the Raspberry Pi, but instead I'm going to focus using the shift register to drive the display.
Two great sources of information on using the HD44780 are this blog entry, and this geocities website, which actually has an HD44780 simulator. That simulator really lets you get a handle on the various commands, and how to give them. It's kind of awesome.