A small quantity of these bacteria are in most soil mix products produced by major manufacturers -- for example: Kellogg's Garden Products, Dr. Earth, etc.
If you want a concentrated source of soil inoculate, the best product I've come across is labeled "Grolife". It comes in tablets or 20lb bags, or by the cubic yard for large-scale applications. When I broadcast the granular on an area of native soil and plants, it appeared that every viable seed -- dormant or not sprouted within a few weeks. What a show of wildflowers! Of course, I had to then pull all the unwanted laurel sumac sprouts out ... You can read more about the product at
http://www.gropower.com/GroLife/GroLife%20Bro.pdf