UPDATE: SANparks confirmed the date von their website!
According to Muzi from Travelwires.com the 2010 South Africa National Parks week will be from 13 - 17 September 2010. The official opening will be at Addo Elephant National Park in the Eastern Cape.
South Africans will have free access to all National Parks in South Africa managed by SANParks, except for Boulders in the Table Mountain National Park. Free access will not include any guided walks, safaris or accommodation and will be granted to all South African day visitors on production of their ID book.
The parks throughout the country will be pretty busy during that week, so International travellers should keep it in mind.