chays:
Everything I read about this ISP assumes I know more than I do. Can someone please give me a simple idiot-proof set of directions so I can get this working even if I don't understand what I just did? Something like: "get an xxx connector and wire it on the breadboard to pins blah-blah, then plug in the ISP and start Z program and tell it to burn." I think I'm that competent.
That's basically it...all you need is to connect the ISP connector to the corresponding pins on the chip, select "AVR ISP mkII" in the IDE and you're done!
Look at the second image in this thread for how I once did it on a breadboard: http://arduino.cc/forum/index.php/topic,125212.0.html
(OK, that's a Tiny85, not a Mega328 but the principle is the same...)
The chip and ISP connector pinouts are here: http://www.akafugu.jp/images/microcontroller-reference-sheet.png
nb. The ISP connector shown there is the 'male' version, the connector from your programmer will be backwards because it plugs onto that.
Here's another guide: http://robotics.org.za/image/cache/data/AVR%20ISP%20Programmer%20connections-500x500.jpg
Identify the +5V and GND pins with a multimeter to make sure you get them right. The red wire on the cable should be +5V, the GND wire should go to outer metal case of the USB plug. Don't connect it up to USB power until you're absolutely sure you have those two connections right. You can mess the other ones up without much harm, but not the power.