USCIS Service Center Operations indicated on a May 15, 2013 call with AILA that as of Friday, May 10th all data entry was completed and receipt notices have been sent. Rejection notices have also started to be sent out. Please allow until the end of May for delivery of receipt/rejection notices.
USCIS has started the data entry process for H-1B petitions selected in the lottery. Premium processing cases are being handled first and data entry for those cases should be completed by April 15. USCIS announced on March 15, 2013, that the 15-day premium processing clock will start on April 15. (AILA Doc. No. 13031549)
At the AILA Spring CLE conference on April 12, 2013, Donald Neufeld, Associate Director of the Service Center Operations (SCOPS) Directorate, informed the audience that data entry for non-premium processing cases will begin after the premium processing cases are entered. Data entry for non-premium cases will likely not be completed until sometime in May, and rejection notices for petitions not selected in the lottery will be sent out after that. Please note that when the cap was reached on the first day in 2008, USCIS did not complete data entry and issue receipt notices until late in May. (AILA Doc. No. 08061261)
Non-premium processing cases can only be converted to premium processing after a receipt notice is issued.

Source: AILA http://www.aila.org/content/default.aspx?docid=44049