Aura for Symbian is not available yet. The hurdle is with Ovi Store limitations on application size. We are working with Nokia to solve this issue. In the meantime, we will provide you with a free update to Mobile Maps 8.2. This will also include free map update
I am also waiting for this navigation for Symbian ^3, i have installed it to my brother's Samsung Galaxy S and I must admit that it looks great. The nicest feature is, that mountains and other topografical objects are shown when you are using navigation.