From: Jaimie Vandenbergh on
To follow up a conversation in April or so: I paid O2 to unlock my
PAYG 3GS running 3.1.3 back then, but I never got the "You're
unlocked" message in iTunes and had to continue using ultrasn0w to
unlock and use my Voda sim. Which concerned me a little.

But good news for me - I just updated to iOS4 and iTunes activated and
unlocked correctly. Hurrah! For safety's sake I did use PwnageTool
4.01, but set to just jailbreak and not do any unlock tricks.

Cheers - Jaimie
--
If you can't beat your computer at chess, try kickboxing