Summary
The Describe function returns Workspace Properties for Folders.
A Folder returns a dataType of "Folder".
Code sample
The following stand-alone script displays some properties for a folder.
import arcpy
# Create a Describe object
#
desc = arcpy.Describe("C:/data")
# Print the dataType and a workspace property
#
print "Data Type: " + desc.dataType
print "Workspace Type: " + desc.workspaceType