Your candidacy is a 'wild card'. It's really hard to say what your chances are since there isn't exactly that many school teachers applying to b-school in any given year to benchmark you against.
In your case, it really comes down to two things:
(1) How well you execute your application. You won't be the first or only applicant who doesn't have any business (or corporate) experience. Adcoms don't expect business experience -- what they do expect however is that you have a clear idea what it is you want for your future - both in terms of crystal clear and specific career goals as well as well articulated reasons why you'll get so much out of an MBA. They want this out of all applicants, but they especially want to see this out of non-traditional applicants like yourself - especially if you don't have much business experience.
(2) Luck. Every applicant needs a bit of luck, but in your case, how an individual adcom sees you can vary far more widely than say a banker, consultant or engineer (where the adcoms can get to a consensus decision pretty quickly and consistently).
You've listed a decent set of schools -- since you are a 'wild card' the admissions results can be a lot more random for you -- you may get into the hardest school of the bunch like Columbia, but rejected at UNC or UT (the easiest to get into of the bunch).
Alex Chu
alex@mbaapply.com
www.mbaapply.com
http://mbaapply.blogspot.com