This is a quick run_through on how to set up an ESP8266 Wifi module using the Arduino IDE.
With Arduino IDE version 1.6.5 it is possible to use the Arduino environment to download programs not only to the Atmel family but also to 3rd party Mcu's and importantly the ESP WIFI series.
FIre up an Arduino IDE version 1.6.5 or later :-
On the preferences tab be sure to copy and paste the URL below into the Additional Boards Manager URL entry box:-