title: How to change Xcode Install destination? (When installing iOS 4.x beta for example)
body: <p>I am working on a project using iOS3.2 SDK and also want to test my app in iOS4.2 beta.
  So I installed Xcode and 4.2 SDK but it replaces previous Xcode installation. Up until now it was ok since I was not busy with these two things. But now I need both.
  How Do I change Xcode (with iOS SDK 4.2) install destination? </p>
  
  <p>I was expecting a button "change install destination" during install but only installation disk partition is changeable. (No folder can be chosen). </p>
  
  <p>Is this possible?</p>