The circuit contains 2x TRW-24G modules, 1x AT90S2313 microcontroller and 1x MAX202 TTL to RS232 voltage level converter. When you power-on this circuit, the AVR it will configure the IC1 as receiver and IC3 as transmitter. I’m not gonna give you any more technical specifications because they are well documented on the authors page. I say you give it a try when you need to setup a wifi connections between AVR’s.
Experimenting Wireless Comunications With AVR ATtiny2313: [Link]