I was in Grad school in Ohio at the beginning of 2006 until May where I was getting a stipend.

Now I moved back to Maryland and have a full time job and own my own business.

To I have to file taxes in both states even thought my perment address has always been in Maryland?

Plus I want to use TurboTax, any opinions on the software... good bad?

Yes, you need to file in both states. You will pay tax to Ohio as a nonresident. The taxes paid to Ohio can be claimed as a credit against your Maryland tax.

IntlTax's citation is accurate UNLESS you established residence in Ohio while in graduate school.

If you did that, then you will pay as a part-year resident in Ohio and as a part-year resident in Maryland. Yu pay taxes on the income earned in each state respectively. Be sure to provide each state a copy of the other state tax return to show both how your total salary is accounted for.