One of the most well known routes is the Wolfberg cracks. It's so well known I'll give only a summary: go to Sanddrif, look up, and keep climbing the 1-in-1 slope till you get to the cracks about one or two hours later. To do this route in really bad style, you can forget to take a waterbottle, go at midday, be totally unfit, gawk at the rock climbers, and only do the wide crack (Adderley Street, also known as the Gaper Crack). Some tips on good style: rather go up the narrow crack (it's a bit off to the right and quite tricky and tight in places), and try a tributary of the wide crack on the way down. And don't forget the waterbottle - it's a dry route.
If you decide to go to the Wolfberg Arch, be warned that it's a Long Way from the cracks - but well worth it. For the adventurers, try a scramble up to the Wolfberg summit about 1 km from the arch. It's like another planet - called The Maze...
Wolfberg Arch can also be reached from Driehoek farm at the other end of Wolfberg. The route is still very long, but it takes you through a fantastic valley of cedar trees and rock formations. Overnight at Die Rif if you prefer not to do a day walk.
The Maltese Cross is another popular sight, but such a straightforward climb that there's really nothing to tell. Maybe you should try this one by moonlight instead.
By the way, the Wolfberg Cracks include some of the best rock climbs in the Cedarberg.