The 2009 version of the US GAAP XBRL Taxonomy was released by XBRL US about a week ago. That page has information helpful in the general use of the taxonomy:
For some reason, a pointer to the web version of the taxonomy (such as this for the PRIOR TAXONOMY http://xbrl.us/us-gaap/1.0/ WHICH POINTS TO THE PRIOR TAXONOMY or this one which points to the IFRS taxonomy http://xbrl.iasb.org/taxonomy/2009-04-01/) is NOT being made available.
Eventually, I am going to build some extension taxonomies which make working with the US GAAP Taxonomy easier. Not sure when I will get around to it.