This unit is a higher-capacity version of the ATmega168 - more than TWICE the flash memory for sketches (30K available instead of 14K), TWICE the RAM (2K instead of 1K), TWICE the EEPROM (1K instead of 512b)
Looking for Atmel AVR microcontrollers? We've got them! They're really, really good. Truly. And pretty inexpensive, too! Solarbotics has bags of them. Well protected, anti-static bags of them!