See: https://hackaday.io/project/3352-esp8266-development-pcbs/log/17066-programming-esp-with-arduino-ide for updates...

Looks like we will soon be able to use the little ESP8266 as a standalone device (no additional microcontroller required) and that make the WiFi sensor so much more practical... Just write your program in the Arduino IDE, upload to ESP and off you go...

...