title: How to upgrade Xcode 3.1.2 to Xcode 4.4.3
body: <p>New to iOS, Have downloadex xcode 4.3.3 ie: xcode_4.3.3_for_lion.dmg,  already the Xcode is present in this machine of the version 3.1.2 [ which i get from spotlight].</p>
  
  <p>Question:
  If i want new Xcode 4.3.3, then all i need to double click on xcode_4.3.3_for_lion.dmg, and then click on Xcode.</p>
  
  <p>How can i make Xcode 4.3.3 is a default version, and remove the old 3.1.2 version?. </p>