Summary
If the text file contains tabular data, the Describe function returns Table Properties and Dataset Properties for Text Files, otherwise refer to File Properties.
A Text File returns a dataType of "TextFile".
Code sample
The following stand-alone script displays some Text File properties for a text file that has tabular data.
import arcpy
# Create a Describe object from the text file.
#
desc = arcpy.Describe("C:/data/evac_table.txt")
# Print some table properties
#
print "HasOID: " + str(desc.hasOID)
print "\nField names:"
for field in desc.fields:
print " " + field.name