I live in Pietermaritzburg and have only been climbing for a few months.
MCSA's KZN site has a descent list of climbing routes, see
http://kzn.mcsa.org.za/climbing/route-guidesThe sites that I know are roughly as follows (I haven't climbed at all of them):
Drakensberg Mountains (crumbly rock with poor protection and harsh weather - my area of the world!)
Monteseel (the main climbing spot - over 300 routes, halfway between Durban and Pietermaritzburg)
Hilton/Howick Falls
World's View (the spot where I normally climb as its close to where I live - the routes are nice and well protected, but not very high)
MCSA KZN section does lots of Drakensberg climbing, I know they are doing Rhino Eastern Arete Route (about a grade 10) next month.