I've got a little 4:3 rear view display and it uses analogue inputs. I watched Ben Heck take a display from analogue to digital, so I want to try it myself. Attached are pictures of the board, one being the full board, the other being some unused pins. If i'm going to hack this thing, I'm thinking I'd have to start there. but I don't want to just put pins there and possibly short the thing. How should I go about this?
No - you start with that main IC - the AMT630. Google it - find the PDF of the datasheet. From what I can see, it is the video display controller, and it has a built in microcontroller that can be programmed in some manner. The program is stored on external flash or eeprom. There's only one other chip on that board that looks like it can be such a beast, so look it up, too.
Then go from there.
Note: According to what little I read - that display controller does not have any digital inputs, only analog inputs. But I haven't found the actual datasheet yet.
Be sure to review any "teardown" articles or forum postings, etc - that you may find. They might lead to further information on the chips, etc.
You may find that the programming data lines do lead to those unused headers - but you first need to do as much research as possible on what that IC is, and how it works, and how you can control it or program it. It won't be a simple process, but this is an ideal project to start your reverse engineering/hacking "career" with.
Good luck. 
Here's some more help - the flash is the PM25LD020 - here's the datasheet:
http://www.chingistek.com/img/Product_Files/Pm25LD010020datasheet%20v04.pdf
Still looking for the AMT630 datasheet...
Ok - according to this teardown forum thread:
...it's a clone of the "MST703" - here's the datasheet for it:
http://www.datasheet-pdf.com/datasheet/Master/770936/MST703.pdf.html
Yeah - I guess I did the work for ya - but use this as a learning opportunity.
Hmm - but according to that datasheet - there is a digital video bus - pin 26 (clock) and pins 27-34 (digital bits 0 - 7 respectively - as an ITU656 video data bus - see page 7 of the datasheet). Most all of the other inputs, with the exception of the SPI inputs - seem to be for analog signals only. There are a few GPIO pins (see page 8). Inputs are 5 volt tolerant (so you can use a regular Arduino) - but the power to the chip is 3.3 and 1.2 volts - so keep that in mind as you experiment and probe.
I'll leave the rest for you to figure out - believe me, you have quite a large task ahead of you! Again - good luck!