Really nice application by Nokia that tries to make the move from iOS, Android or Blackberry as easy as possible.
Today, we have Welcome Home for Windows Phone: a truly innovative app from Markspace to help new Lumia owners migrate to their new phone. With Welcome Home, you just plug in your Lumia to your computer (Mac or PC, your choice) and the application handles moving your contacts and personal data – quickly and easily. – Nokia Conversations
Welcome Home for Windows Phone will handle contacts, calendars, pictures, songs and videos to Microsoft Live. What’s even cooler is that this application will scan the apps on your old phone and search for the same applications or closest match. It will then automatically create scannable QR codes (QR code reader baked in to the Windows Phone UI) where you can easily download the applications.
Using Welcome Home for Windows Phone seems to be really straightforward and easy to use, but you can check out the instructions from here
Download Welcome Home for Windows Phone for your PC or OSX from here