I am a graduate student in Maryland, originally from India and with F-1 visa. I would be on OPT from mid-June 2012 (graduating in May 2012). I am considering job offers and wanted to know the total tax deduction specifically for this position: temporary 6 month position paying $2000 per month in DC. I have a similar offer, but in Maryland, would the tax deduction be nearly the same?

F-1 students do not pay FICA taxes for 5 years. Federal income tax rate is same irrespective of the state where you work. Your U.S. Tax Return: U.S. Tax Filing Requirements for Non-Residents

Washington does not have state income tax. For Maryland income tax rate check at the state web site.