African Growth and Opportunity Act and Millennium Challenge Act Modernization Act or the AGOA and MCA Modernization Act This bill directs the President to establish a website for the collection and dissemination of information regarding the African Growth and Opportunity Act (AGOA). The Department of State is urged to promote the use by eligible sub-Saharan African countries of the benefits available under the African Growth and Opportunity Act. The President is urged to: facilitate trans-boundary trade among eligible sub-Saharan African countries; provide training for business and government trade officials on accessing AGOA benefits; provide capacity building for African entrepreneurs and trade associations on production strategies, quality standards, and market development; provide capacity building training to promote product diversification and value-added processing; and provide capacity building and technical assistance funding to help African businesses and institutions comply with U.S. counter-terrorism policies. The Millennium Challenge Act of 2003 is amended to permit an eligible country that has entered into a Millennium Challenge Compact to enter into one additional concurrent compact under specified conditions. Regarding a subsequent nonconcurrent compact, a country's eligibility shall be based on significantly improved performance across the criteria relevant to selection for the preceding compact. The bill establishes, beginning with FY2013, new assistance criteria for a low-income or a lower middle income candidate country eligible to enter into a Millennium Challenge Compact with the United States. The Millennium Challenge Corporation shall: (1) before selecting a compact country, provide the Board of Directors with information regarding the country's treatment of civil society; and (2) submit an assessment of the feasibility of developing partnerships at the sub-national level within candidate countries.