i also decided to e-mail a number of schools i was interested in re-applying to. i think e-mail is probably better because it gives admissions more time to actually look at your app (if they decide to give you the time of day) and, to me, it seems less pushy. i would also agree that, if you e-mail, it should be to an admissions director or dean, not just general admissions. ask what you can do to improve your app, but also try to mention why you're so interested in attending that school. i think that'll help your cause a lot.
so, yeah, i'd advocate making some contacts - in my case, 3 of the 4 schools i was accepted to this year were schools whose deans i contacted last summer. best of luck.