The Foreign Office is responsible for foreign and European affairs in Germany. Here you can find information on visa requirements, a list of countries with a visa requirement for entering Germany as well as application forms for downloading.
The Federal Agency for Migration and Refugees has compiled a list of important information about social security and access to the labour market.
EURES (European Employment Services) is a cooperative network that aims to promote the mobility of employees in the European Economic Area. Its members include public employment agencies, trade unions and employer associations. The network is coordinated by the European Commission. You can get English-language information and advice about job opportunities and living/working conditions in the European Economic Area here.
The federal ministries for "Economy and Energy" and "Employment and Social Affairs" have developed a Welcome Portal for immigrants in cooperation with the “Bundesagentur für Arbeit” (Federal Employment Agency). Here you can find important information on social security.