Mobile phones: Is it worth getting them unlocked?

[Guest sozzyhall]

Hi, we just moved here and I have an I-phone 4 from the uk which was with orange....I called them up before i left uk and paid £15 for them to unblock it. Once in Oz I brought a virgin pay as you go sim, its $20 a month to top up, calls and data usage are really cheap, plus my boyfriend brought the same chip and we can call each other for free. Then all we had to do before we used it was update with i-tunes sync on our laptops! Easy as that