I have an Arduino Pro Mini 328 5V/16MHz... two actually. Today I tried uploading a sketch for the first time and received the dreaded "avrdude: stk500_getsync(): not in sync: resp=0x00" error message. Before you go through all the voodoo that I had to, I want to tell you some quirks with the Pro Mini that you should know.
According to < http://arduino.cc/en/Guide/ArduinoProMini > "If using the FTDI cable on Windows, you'll need to make one configuration change to enable the auto-reset. With the board connected, open the Device Manager (in Control Panels > System > Hardware), and find the USB Serial Port under Ports. Right-click and select properties, then go to Port Settings > Advanced and check Set RTS on Close under Miscellaneous Options." It doesn't say what vintage of Windows; but I sure don't have that option on my Win7x64 machine, so that's no good for me.
According to < http://arduino.cc/en/Guide/ArduinoMini > "Reset. Whenever this pin is connected to ground, the Arduino Mini resets. You can wire it to a pushbutton, or connect it to +5V to prevent the Arduino Mini from resetting (except when it loses power). If you leave the reset pin unconnected, the Arduino Mini will reset randomly." On my schematic for the Pro Mini, the reset pin is held up to +5V though a 10K resistor.
It continues, "The circuit shown here is the basic setup for an Arduino mini connected to a USB-to-serial converter. The 0.1uF capacitor from the reset pin is connected to the RTS pin on the mini USB adaptor. This enables auto-reset when the serial port is opened, meaning you don't have to press the reset button every time you upload new code. If it gives you problems, you can remove it, and press reset every time."
Are you kidding me? "Connect the RTS pin on the USB-to-serial converter." I don't have that pin available because my converter is sealed in plastic. Or, it says, I can "Press the reset button every time." Yes, that's right. "To upload a new sketch to the Arduino Mini, you need to press the reset button on the board immediately before pressing the upload button in the Arduino environment."
Perhaps, they say, my board was, "burned" with the wrong bootloader, in which case I, "need to buy an AVR-ISP (in-system programmer), USBtinyISP or build a ParallelProgrammer." No modern computer has a parallel port anymore, but go to this page anyway for a real exercise in frustration: < http://arduino.cc/en/Hacking/MiniBootloader >
Maybe you like to press the rest button all the time. Me, I think this situation is ridiculous. I hope I'm wrong. I hope that someone will tell me that I'm wrong, and I await their gentle correction. Until this is fixed, however, if you want to have fun, I suggest that you stay away from the Arduino Pro Mini.