AZ Displays ACM2004D

This display module apperantly has quite a bit more to it than I was expecting... I was hoping for a simple display that could be used over serial when I picked it up, but that doesn't seem to be the case.

I still want to use this with the arduino, but I can't seem to comprehend how it's supposed to be used. Ideally I'd try to use less than 12 MCU pins to operate it, as well, but I can worry about that later...

It confuses me, because this display module evidently has some sort of internal memory, and I'm not sure how to use that, or to cause text to be displayed.

This display you have is an HD44780 display, which you need 6 pins to drive, not a serial display that you can run over a 2 pin TTL serial port. Yes, it will waste some pins but also it is much cheaper than a serial LCD. Here is a tutorial:

http://www.ladyada.net/learn/lcd/charlcd.html

Later you can get a serial back pack for it if you want.