My wife is a Maryland resident and has income from a K-1 Limited Partnership that is located in Ohio. The partnership paid her estimated taxes on income to Ohio. Does she owe taxes for this in Maryland, too? Also, if we have a bank in Florida, do we pay Maryland taxes on interest earned at this bank?

To Maryland, you must report your worldwide income for the year.
Read: Your U.S. Tax Return: Working or Living in Two or More states (http://taxipay.blogspot.com/2008/06/working-in-two-or-more-states.html)

Additionally, you may need to file an Ohio tax return to claim a refund for the taxes paid to Ohio.

If you are not exempt from the Ohio tax, you CAN claim a credit on your Maryland return.