http://www.ebay.com/itm/ESP8266-Flasher-Rev2-/262173027744
I have the rev 1 version that has a larger (standard size) usb connector.
This new rev 2 uses a micro usb connector.
I really like this module as it has the usb to serial conversion, 3.3v regulator, flash and reset buttons.
At least I am happy with mine but YMMV
dwight