On orange, is it free to change to a micro sim?

Well i'm looking to get a sim free iphone on my £31 a month contract but does it cost to change it to a microsim?

Orange usually charge around £10 to send you a micro sim. Sometimes they will send this for free but then charge you the £10 when you go to register it.
Your other option is to visit a repair shop that can cut your normal sim into a micro sim.