NativeToolkit no longer available?

Hi there. I may missing something obvious here, but I've been hunting around for several hours trying to find a way to open a standard xcode view controller from Unity. Everything I read points me to Prime31's native toolkit, but I can't find a download or purchase location for that specific plugin anywhere.

So two questions; firstly is there any way built into Unity that I can open a standard view controller? And secondly, if not the where abouts can I find the native toolkit?

Thanks.