I don't know of anything in particular. You've probably already done this, but if you search google you will get a few applications. More databases than patient information.
I would try searching google for "chiropractic iphone" or "soap iphone" and see what comes up. There are a few options and more for nurses, chirporactors, etc. than acupuncturists specifically.
If there are not an incredibly large number of patients you could probably store the patients files within google apps document section and access them and edit them with the phone. It would be a free solution but probably not as slick as it could be. If you give each patient a patient number you can store the soap notes in individual documents by number.
You do need to be careful, however, not to violate HIPPA rules regarding online access of files. So I would read them closely particularly if you are talking to an online database to access your patient files.