...and while that's a good point, you get into the question raised by a post below: Why would someone ask to be released without knowing what they will be earning beforehand? You could be taking a hit financially if you would be making less for the remaining school year at the new school than you are at your current school. I guess the OP could ask the new school what date they expect him to be on duty...then it should be easy to figure out what they're making using what is on the website.
But...and I don't know the OP's reasons...if the current school is a horrible situation, it might not be that much of an issue to earn a little less in order to get the heck out of Dodge.