This is primarily a bouldering area that lies in the Canyon to the East of Topanga Canyon Blvd (27). I understand there are some top rope options in the area too.
If you park in the town of Topanga, head south along Topanga Canyon Blvd for approximately 1/2 mile and look for a small use trail on the west (right) side of the road. This leads to a graffiti covered culvert that will take you under Hwy 27 and down to the canyon bottom. Once at the bottom, head right (downstream) for about 1/8 mile or so and you will run into what I have dubbed "Area 1". The boulders are not purple here but there is ample evidence of climbing and the problems look to be relatively moderate. Continue downstream for another 1/8 mile and you will come to the Purple Stones North area. The Purple Stones South area is found approximately 1/8 mile downstream from this area.