This is from the NRMP website.
Note: Any contact between programs and unmatched applicants (or their designees) prior to 12:00 noon eastern time, Tuesday, March 16, 2010, is a violation of the Match Participation Agreement. Contact between programs and matched applicants prior to the general announcement of 2009 Match results at 1:00 pm eastern time Thursday, March 18, 2010 also is a violation of the Match Participation Agreement.