I am travelling to Germany for the World Cup. I need to keep in touch
with my businesses at home. For this I need to be checking the
internet very often. What are the options for wireless internet in Germany?

Ideally I would be able to log-in everywhere - eg not just at T-Mobile
HotSpots. Is there a carrier in Germany that offers Country wide
wireless internet for one month? If not, what is the best option for HotSpots etc

I'm in Germany right now about 40 minutes north of Munich.  I do not
believe there is a nationwide wireless internet available here, and
the Internet capabilities are a bit behind the US.  However, there are
some places that are available to hook up a laptop to--i.e. coffee
shops such as Pow-Wow.  There are also many internet cafes all over
that give rates from 1euro to 3 euro per hour.  Have fun at the World
Cup, I'm jealous you found tickets.  If you have any more questions
you can email me. I'm a student from the US here studying abroad. 
Enjoy the time in Germany!