FWIW, here's a batch file I use...
echo off
echo ** Write optiboot (Arduino Uno) bootloader on ATmega328P chip
avrdude -c usbtiny -p m328p -v
echo ** Chip erase
avrdude -c usbtiny -p m328p -e
echo ** Set fuses
avrdude -c usbtiny -p m328p -U lfuse:w:0xff:m -U hfuse:w:0xde:m -U efuse:w:0x05:m
echo ** Write bootloader...
rem avrdude -c usbtiny -p m328p -U flash:w:optiboot_atmega328.hex
avrdude -c usbtiny -p m328p -U flash:w:optiboot_atmega328_westfw_2011-06-15.hex
echo ** Lock
avrdude -c usbtiny -p m328p -U lock:w:0x0f:m
echo ** Bootloader written!
avrdude -c usbtiny -p m328p -v