I lived in MD till August, moved to PA. MD is still withholding state taxes. How do I file the two state taxes?

You must file tax return for both the state unless your income is below filing requirements for a state.

If you are present in a state, then any income earned during this period, must be reported to the state.

To your resident state, you must report your worldwide income for the year. MD may treat your resident for 2008. Check at state web site for residency requirements. Read: Your U.S. Tax Return: Working or Living in Two or More states

Maryland is not withholding the MD taxes; your employer is withholding them. Tell the employer to STOP withholding MD taxes and START withholding PA taxes.