405 rhinos have been poached in South Africa to date

update (13 Jan 2012): According to the online edition of "The Guardian" (UK), 448 rhinos were killed by poachers in South Africa in 2011, meaning one rhino was lost to illegal hunting every 20 hours...

update (30 Dec 2011): The street value of rhino horns is currently around $65000/kg, making it more expensive than gold, platinum and in many cases cocaine.

update (22 Dec 2011): According to South Africa's Private Rhino Owners Association, around 435 rhinos have been killed by poachers in South Africa in 2011. [src.]

update (15 Dec 2011): According to National Geographic's Daily News from 14 Dec 2011, 443 (433) rhinos were killed by poachers in South Africa in 2011 sofar. Out of the 443 rhinos killed in the whole of South Afirca, 244 rhinos were killed in Kruger National Park. [src.]

South African National Parks (SANParks) has announced that a total of 405 rhinos have been poached throughout South Africa to date (06 Dec 2011).
The number of rhinos poached is up by approximately 21.6% from the 333 of the previous year, against an increase of 173% and 47% for 2010 and 2009 respectively. The number of arrests of alleged poachers has also increased from the previous year by approximately 27.3% to 210, from 165 in 2010.
Kruger National Park is the hardest hit area in South Africa with a total loss of 229 rhinos so far. 66 rhinos were poached in Limpopo, 31 in KwaZulu Natal and 26 in Mpumalanga. (via SANParks)

• Kruger NP - 229 rhinos (77 poachers arrested)
• Limpopo - 66 rhinos (26 poachers arrested)
• KwaZulu Natal - 31 rhinos (4 poachers arrested)
• Mpumalanga - 26 rhinos (66 poachers arrested)
• North West - 20 rhinos (21 poachers arrested)
• Eastern Cape - rhinos 11 (2 poachers arrested)
• Gauteng - 9 rhinos (14 poachers arrested)
• Marakele NP - rhinos 5 (0 poachers arrested)
• Western Cape - rhinos 4 (0 poachers arrested)
• Northern Cape - rhinos 0 (0 poachers arrested)