I am trying to get through a tunnel like obstacle and I usually stick to just coordinating time with power, but I would like to kick it up a notch and have an ultrasonic scan both the left and right walls and have it store 2 or more values. From there I would like it to make a decision whether my robot needs to veer right or left until both sides are aligned. How would I go about that? sample code would be awesome, if not, can you guys throw some terminology that I might be able to look up.

Here is what I want it to do (simplified version):

Scan left, readDistance, storeLeftDistance
Scan right, readDistance, storeRightDistance
if leftSide < rightSide
moveright until leftSide == rightSide
else
moveLeft until leftSide == rightSide

Thanks guys

You have a basic bang-bang control feedback loop there, but you might want to consider looking into a PID Controller:
http://www.inpharmix.com/jps/PID_Contro ... obots.html