I just received two off these small ESP-01 boards.
They are part off the ESP8266 family and have relly nice specs:
- ESP8266 chip.
- 2 dedicated GPIOs.
- Serial comms (or 2 additional GPIOs).
- Pin connectors.
- Arduino-compatible.
- PWM, I2C, UART, OneWire.
- On-board WiFi + printed antenna, 802.11 b/g/n, 360m range.
- Able to become a wireless access point.
- Lua and Arduino firmware available.
- Able to run a web server.
- Dimensions: 24.75 x 14.5mm.
- Power: 3.3v. (important!!)
Sources: http://esp8266.co.uk/modules/esp-01/
Instruction for flashing this little fellow can be found on http://www.esp8266basic.com/flashing-instructions.html
And I plan on building this flaching setup