Excel internal values are stored as floating point numbers. So in xlrd, if you want to read Excel date values as Python date values, you should use a method xldate_as_tupleto get the date.
Documentation: http://www.lexicon.net/sjmachin/xlrd.html#xlrd.xldate_as_tuple-function
Here's a general example:
import datetime, xlrd
book = xlrd.open_workbook("myexcelfile.xls")
sh = book.sheet_by_index(0)
a1 = sh.cell_value(rowx=0, colx=0)
a1_as_datetime = datetime.datetime(*xlrd.xldate_as_tuple(a1, book.datemode))
print 'datetime: %s' % a1_as_datetime
myexcelfile.xls A1 , datetime a1_as_datetime.