So I bought an Apple Airport Express (2nd gen) the other day, and decided I wanted to tinker with it.  Well the first thing I found were the UART pads, and soldered up some jumper wire to connect up a FTDI chip to the jumper wires.  Then,  I decided to record the entire boot process which can be found here, http://www.youtube.com/watch?v=5IY1mX3HqXQ

Does anyone here know how I could dump the current bootloader of the device?

Also, I take it I could load up a tftp server on my computer and see if I could reflash the device with openWRT, but I feel that would brick the device.

Nice,

I'd suggest you record a text boot log with the serial console, and post it so it can be dissected.
It looks like the bootloader can be identified, maybe even the kernel (I've not read too carefully
the video, but there's definitely some info available in there.

You should (if wiki admins accept) create a ToH page about it, explaining where the uart pins
are located, what settings you used to get output, etc...

In short, describe what you did so that it's not lost and other people can start from there...

What's the pinout? I might try to get one and get it working.

I started a wiki over at theairportwiki.com it should have all the information you need.