A few hints:

Transportation
- If you borrow a car and want to visit the inner city, you need something called "Umweltplakette". It is a sticker for your car and costs 5 or 6 euro
- It is better to use public transportation with 3-day-tickets

Beer:
- I recommend you Bitburger and Becks.

Language:
- There's no problem with English. All German students learn it at school (so talk to young people ) and the berlins are used to tourists.

Food:
Man, there's really no problem, even if you want to stay with American food

Are you talking about the Maemo Summit?