**EDIT** urquan from reddit pointed out you can use an AVRDude available on their site here: http://download.savannah.gnu.org/releases/avrdude/ ***
For a while now, the easily available builds of AVRDude that I could find have been terribly out of date, and I've been building my own. It just occurred to me it may make sense to release a build here.
This was built from avrdude-6.0.1 on a Linux Mint 15 system using the following commands:
./configure --host=i686-w64-mingw32 AR=i686-w64-mingw32-ar CFLAGS=-m32
i686-w64-mingw32-gcc -Wall -Wno-pointer-sign -g -O2 -DWIN32NATIVE -static avrdude-main.o avrdude-term.o ./libavrdude.a ser_win32.c crc16.c serbb_win32.c -lusb -lm -o avrdude.exe
It was that simple.
The download including libusb, etc. can be found right here: http://cnlohr.net/random/avrdude-6.0.1-cnl.zip
You will still need to install "drivers" on Windows XP, Vista, 7 and 8. There are some ways people have been doing this, but the easiest way I've found is to download win32 lib usb, then run the driver installer and running it right there on the spot.
You can find the driver maker app "inf-wizard" in the "bin" folder of that zip. Be sure to unzip the whole thing. Follow the instructions, selecting the device that matches vid/pid pair: 0x1781, 0x0C9F
When done, tell it you want to install right then.
Note that on Windows 8, you will need to reboot with driver signing enforcement turned off. You'll have to look up another guide for that.
P.S. I HATE WINDOWS, I almost exclusively use Linux. I just have to deal with people who use Windows, so you get to benefit from my misfortune.