Cape Town maps make traveling in and around the city and Peninsula a breeze.
At any tourism office you should easily be able to get hold of many free maps. These maps however would only give you an overview of the main routes.
If you want something more substancial, you should invest in one of Peter Slingsby's maps.
"Many tourist maps available in South Africa are printed and produced overseas. They are drawn by people who have never stepped on African soil, who would not know Cape Town from Calitzdorp or Nyanga from Knysna..." Peter Slingsby
I also own at least four of them and use them quite often. As he is from Cape Town, the maps provide you with additional information like which are the more scenic routes, etc. Retail outlets for Slingsby's maps
The maps below however, are so that you can orientate yourselves.
PS. Cape Town roads are well-marked and you should easily be able to find you way around, even with a bad map!