My dear, mine was less than a month..
I received my 1st notification letter (1st NL)) 13th july, 2012; sent my DSP-122 and DS-230 forms and passport photos 19th july, 2012 and was received at KCC 24th july, 2012.
I got my 2nd notification letter today, 9th of August, 2012 (5:01pm GMT +1)...