Here's some code and schematic to connect your mightyohm.com geiger counter to the Internet of Things (IoT).
If you use the external 3,3 volts, you have to remove the batteries from the geiger counter!
To compile this code, just clone or download the master branch as a zip and ramp up your arduino library. For this code to work, you need the SimpleTimer-library (http://playground.arduino.cc/Code/SimpleTimer#Download) and the ESP8266 added to your Arduino-IDE as a board (https://github.com/esp8266/Arduino, see install instructions)
You need to adjust the settings in the settings.h file.
This code is under MIT license (Christopher Schirner schinken@bamberg.ccc.de) The geiger counter is used at our hackerspace in bamberg (https://hackerspace-bamberg.de)