Exempting from the State property tax a dwelling owned by a public school classroom teacher, if the teacher lives in the county where the teacher is employed; authorizing the Mayor and City Council of Baltimore City and the governing body of a county to grant, by law, a property tax credit against the county property tax imposed on a dwelling owned by a public school classroom teacher if the teacher lives in the county where the teacher is employed; applying the Act to tax years beginning after June 30, 2006; etc.