@hgugger, I used NCSU -- some of their links sometimes give 404 errors, but you can normally get there by going in a different way. Try this link to see if it can get you started http://www.ncagr.gov/agronomi/sthome.htm. I followed their instructions (i did do my front yard and my back yard as separate samples). It was pretty simple --- I took 10 or so core samples, mixed it all up,then filled up the box to the line they had on it. The analysis was free and took about two weeks -- you get the report online. Cost me $9 to send the samples from Charlotte to Raleigh because of the weight! If I lived in Raleigh, I'd just drive it over! You probably will also need to drive over and pick up the sample boxes from them. (The web site says "Pick them up at your county Cooperative Extension office or at the Agronomic Division office in Raleigh."). If you have any problems, PM me.