I was trying to see if I can run latest Xcode 4.2 on a machine running Snow Leopard 10.6.0 by just copying the /Developer folder from my macbook running 10.6.8. So I renamed an existing /Developer folder with Xcode 3.2 to /Developer.old and copied the /Developer with new Xcode from the other box. Changing "Minimum system version" to 10.6.0 in the Info.plist in Xcode's package sort of did the trick, I can run Xcode, but I have a problem with running iPhone apps in iPhone Simulator. It gets stuck on "Attaching to MyApp".
So, I guess something is missing in my "installation". I noticed System Profiler is showing the old version of Xcode in Developer Information, better yet, it points to /Developer.old. How could I update this?