A taxi can be taken from any place or can be called to come pick you up at anytime you want, even weeks.
Here are some phones that you use if you are in need of a taxi:
030 20 20 20 (Taxi Berlin)
030 44 33 22 (Taxi Funk Berlin)
030 26 3000 (Quality Taxi)
03021 02 02 (Cityfunk Berlin)
If you only want to know about them, how they think, what they do you can visit a blog about them (only in German) http://www.taxiblogger.de/
Here are some phones that you use if you are in need of a taxi:
030 20 20 20 (Taxi Berlin)
030 44 33 22 (Taxi Funk Berlin)
030 26 3000 (Quality Taxi)
03021 02 02 (Cityfunk Berlin)
If you only want to know about them, how they think, what they do you can visit a blog about them (only in German) http://www.taxiblogger.de/