Solved--Programing a atmega328 with an Uno and a SD card in the field?

I am looking for a way to program atmega328s in the field. I know how to do it with jumper wires when connected to an Uno that has the chip pulled and the board hooked to a computer.

I stumbled across a post, or page a while back talking about doing this with an uno and a SD card. At that time I did not see a use for it and did not save the page. Now that I have chips in the field some times it would be handy to update their code where they are vs replacing the chips or bringing the whole thing home to where I have a computer.

Anyone else ever do this, or happen to know where I can find the post? It was by one of the more prolific posters on here, but I unable to remember who.

If this is the wrong forum to post in please feel free to point me to the correct one.

Thanks,
Brandan

Here's a pre-made unit sold by one of the forum moderators, Crossroads:
http://www.crossroadsfencing.com/BobuinoRev17/Programmer.html

Here's the tutorial for the DIY version:

That is what I was looking for, Thanks.