yes you need a permit and must have it on you at all times while climbing. It is a free permit and you can obtain it at the Garden of the Gods (GoG) visitor's center on 30th Street, across from the main entrance to the park.
There is no free-climbing (rope-free) or scuttling (climbing of lower rock formations) allowed and there can be severe penalties for climbing w/o a permit. And, as coincidence would have it, I have two friends that are suffering from broken ankles (one each, that is) from falling while scuttling....
I'll post some pics of the GoG, it should be a nice trip down memory lane for ya!