Are you sure about those 74LS125 buffers? LS technology needs 5V to work (you're powering it with 3.3V) and it doesn't like input voltages higher than the supply rail (i.e., 5V coming from the ATmega328).
--
The Rugged Circuits Yellowjacket: 802.11 WiFi module with ATmega328P microcontroller, only 1.6" x 1.2", bootloader