You can apply for a USA Green Card Loterry 2013 from October 4, 2011 to November 5, 2011
Please remember :
One and ONLY correct site is with „.gov“ and that service is for FREE ! Never pay for „green card loterry apply“ to anybody. Store well your Confirmation number, it can not be resend to you from US Goverment, even if you win !
In past times, US Goverment did not sent you any notification that you won, but now i can see there is information, that they are notify you, if you will win.
But be really careful ! There is nothing to pay after you win.. There is very much companies, that somewhere stole your email and send you a fake notification and wants some payment.
I suggest you to follow these steps:
1.) read INSTRUCTIONS FOR THE 2013 DIVERSITY IMMIGRANT VISA PROGRAM (DV-2013) 
2.) use Photo Validator
3.) Begin entry
or you can visit this site on www.dvlottery.state.gov
Good luck ! LuCaS