Once upon a time a long time ago I minored in Soil Science and Range Management for three semesters. One of the things that stuck with me through the years is that for a very inexpensive price the Texas AgriLife Extension Service will do soil analysis (this after spending hours in the lab learning how to do the chemistry ourselves). I do not know if they do this for people living out of the state of Texas. I am sure you can call to find out. However if you do not live in Texas you might want to check with your State’s own agricultural extension service. Every state has one (http://www.csrees.usda.gov/Extension/). Since each region has different soil types I think I would rather rely on local experts. For those living in Texas or surrounding areas here is the link to get your soil tested.
Thom's Gardening Corner 