The target pace during a race is fairly easy to calculate. As you pointed out earlier, it's really just simple math, and any number of online running calculators can do that for you. Here's an easy one for half and full marathons.
http://www.smartpacing.com/index.php?page=PacePrediction The one thing I always tell people to be cautious of is that the pace charts assume you run exactly the race distance. Since most people can rarely if ever do that, you need to run a bit faster than the mathematical pace. For example, a 9:07 pace will get you in 30 seconds under a 2-hour half. That's cutting it a bit close since if you run only a few hundred yards more than 13.1 miles due to weaving or not following the exact tangents, you'll be over 2 hours. That's why for whatever your distance and calculated pace, you should run 5-10 second per mile faster to make sure you hit your time goal.