You may send andreas _at_ biessmann _dot_ de a mail or contact him by one of the various instant messanger accounts.
To send me gpg encrypted mails you can get Andreas Bießmann‘s öffentlichen Schlüssel (0xBB28B849) from a keyserver (or just download it). Fingerprint of this key is:
B702 38EF 914B D16F B4ED 9C24 30DD 58A7 BB28 B849
You can find more work-related information about me at XING profile of Andreas Bießmann.