This schematic diagram shows the ATmega32 in its minimal circuit. The ATmega32 is using its default settings, which includes the internal 8 MHz RC oscillator. The circuit works with ATmega16, ATmega32, ATmega164, ATmega324, ATmega644, ATmega1284, and ATmega8535 MCUs. Please note that although the ATmega16 / ATmega32 are pin compatible with the ATmega164 / ATmega324 series, they are not machine code compatible, as the register addresses have changed. The x4 series also sports a second USART, and pin change interrupts. There is an ExpressPCB design file for a full 40-pin AVR development board, with schematics, that supports the ATmega16, ATmega32, ATmega164, ATmega324 and ATmega644, ATmega1284, and ATmega8535 microcontrollers. The code you will find there will allow you to use the Arduino environment to program your ATmega32 or ATmega644 microcontroller.
Here you can find the current ATmega32 datasheet
This is the schematic for the 40-pin development board, which can use any of (at speed):
It provides some switches, pots, and LED's but is shown here as an example of the ATmega32 with a crystal. The output connections show Arduino pin numbers as well.