QUOTE(PeeEl @ Dec 9 2009, 01:28 PM)
In case you are not aware, UK iPhones are NOT officially unlocked.
What forumer PeeEl trying to say is that UK set is not officially unlocked like Maxis set. Officially unlocked means you can just put any sim card and it will detect the signal. Locked phones are phone which can only use the intended telco i.e. vodafone, virgin, O2 etc.
Jailbreak on the other hand is to open up the phone so you can modify the system files to enable unlocks, mods, themes and apps not supported by Apple.
If you get UK iPhone, you need to
jailbreak and
unlock the phone thru pwnagetool or blackra1n. Right now with the new 3Gs having a new bootrom, you need to rejailbreak again using blackra1n everytime you reboot the phone (quite a hassle). You will also be left out if Apple put out new firmware and if you upgrade to a new firmware (which sometime include a new baseband), you'll stuck with a locked phone until someone comes out with a new jailbreak and unlock (if you're out of luck, you can't even unlock with the new baseband). For locked phones, jailbreak is the 1st step followed by unlock. Without jailbreak you can't unlock the phone, and without unlock, you'll end up with an iPod Touch instead.
Maybe you can read
this especially
Section F