As a very unsupported feature, I believe there are a few GPIO pins available on what used to be the NAND flash chip, but is now just an unpopulated pad. I count around 14 pins on that. You might be able to find some other unused pins, there are a couple of others. I believe you could even turn the UART pins into GPIO pins as well, and depending on what other devices you needed, you could turn other outputs into GPIO as well.
The absolute easiest way to manipulate GPIO pins (or anything else on the CPU) is to use a program called regutil, which is just a glorified PEEK and POKE. You'll want a copy of the Applications Processor Reference Manual (which you can get from http://www.freescale.com/webapp/sps/sit … de=i.MX233 ). Figure out which pin you're looking to manipulate, then use regutil to (1) Turn that pin into a GPIO, (2) Set the pin for input or output, then (3) read or write that bit. There are a couple of scripts where I do just that, particularly backlight_full.sh or enable_usb.sh.
Another option is to just pick up a Phidgets board. I've never used one before, but I enabled that kernel module because I thought someone else might find a use for it.