You can find comprehensive information about german visa regulations on the website of the German Federal Foreign Office. The information here is taken directly from these pages.
A visa is not required for visits of up to 90 days in an 180‑day period for nationals of those countries for which the European Community has abolished the visa requirement. There is a table of countries whose citizens require/do not require visas to enter Germany.
As a rule, missions require between two and ten working days to decide on an application for a short stay visa. During the peak travel season there may be a waiting period for making an application to a German mission. Persons requiring a visa to enter Germany should therefore submit their applications in good time.
The German Federal Foreign Office provides a FAQ-Section that can help you further.