Atmega328p

Info on the ATMega328p hardware:

data sheet

http://attie.co.uk/file/ATmega328p.pdf

icsp pins

connecting to bus pirate for use with avrdude

brown		miso	1		2	vcc (3.3v)		white
yellow		sck	3		4	mosi		orange
red		reset	5		6	gnd		black

pin 2 can use the gray wire for 5v instead of 3.3v if your circuit is okay with that

pin mapping:

source: http://arduino.cc/en/Hacking/PinMapping168

firmwares:

The arduino environment comes with a few variations of the firmware (<path to arduino>/hardware/arduino/bootloaders/atmega)
load them like this:

$ avrdude -c buspirate -P /dev/ttyUSB1 -p m328p -U flash:w:ATmegaBOOT_168_atmega328_pro_8MHz.hex

This table shows which arduino (that I own...) uses which firmware

Filename	Processor	Arduino Boards
ATmegaBOOT_168_diecimila.hex	ATMega168 @ 16Mhz	Diecimila, Duemilanove, Nano
ATmegaBOOT_168_atmega328_pro_8MHz.hex	ATMega328p @ 8Mhz	Pro Mini, Fio

resources

https://www.mainframe.cx/~ckuethe/avr-c-tutorial/
http://hintshop.ludvig.co.nz/show/buspirate-avr-programming/
http://itp.nyu.edu/physcomp/uploads/6pinAVRproghead.jpg
http://dangerousprototypes.com/bus-pirate-manual/
http://www.ladyada.net/library/arduino/bootloader.html