Working in Germany
Nationals of the EU, Liechtenstein and Switzerland are treated like Germans and therefore do not require work or residence permits, however you must register your stay with the local authorities within three months of your arrival. If you are from a country outside the European Union, obtaining a work permit for Germany can be problematic and slow. Work permits are issued on an individual basis only and do not cover any other dependant family members. All other family members must apply individually if they wish to work.
Make sure to apply as soon as you know you are heading for Germany. The application process can be time consuming and you may wait some time before receiving a reply to your applications. There are many job search engines and many newspapers have their "Career" sections online. An application pack for a German company is very different from the usual CV and Cover Letter format found in English speaking countries. The following link provides a helpful guide to job hunting in Germany!
A big plus in your search for a job will be your knowledge of German. Do not assume that everyone here in Germany speaks English, it just isn't true. You will need to learn the language in order to facilitate your day to day life and to find a job with the majority of companies. There are excellent online resources for before you arrive and excellent language schools offering intensive courses once you are here.
Finding a student job
Finding part time work is generally not difficult as the German university system is based on a flexible schedule. As a student you do not need a work permit. However, the amount of money you are allowed to earn is strictly limited. If you earn more you will be treated as working full time and are subject to taxes and more expensive social security deductions. Ask your employer: they will know.
Universities often help with organising appropriate internships (i.e. magazine internships for media studies), esp. during the summer vacation. Vacancies are promoted on newspaper websites, via student unions or directly via the university. Some language schools offer a combination of language course and internship!
Taxes and Social Insurance
Germany has a progressive tax system with bands varying from 0%-42%. Everyone in gainful employment in Germany will make compulsory contributions to a social insurance fund which will cover medical treatment, pension contributions etc. Top up insurance is available if you wish to receive more preferential treatment (choosing a specific doctor, etc.). It may be advisable for Expatriates to consider additional medical insurance in case of the need for repatriation, etc