Withdrawing Law School Applications

Does anybody know the polite way to withdraw a law school application? I don't want to burn bridges as who knows what will happen if we go with the 'Class of 2011 Plan.' I also don't want to hold open slots that people on the wait-list are desperately waiting for. Should I just say, "Thanks, but no."? Should I call/e-mail/write? One of my acceptances had a little form to mail back to them. Check this box if your coming, check this box if you aren't. If you aren't check one of the following boxes: continue other education/attend another school/job/deployment/other (please explain) What about the others. Advice would be appreciated.