Does it seem like, with each update to the iPhone, it takes longer and longer for Jailbreaks and SIM Unlocks to shake out? Here's the latest for those of you who want both a SIM Unlocked phone and the latest OS from Cupertino - a SIM unlock from Zibri. There's caveats, though, as you can see:

This is Version 1.3 Of anySIM.
This version unlocks baseband 4.03_13_g
It's only for bootblock 3.9 don't use on 4.6
To use it, upgrade the baseband then
put the iPhone in airplane mode and run it !
It works also in JB 113 OS... - Zibri [via]

Short version of the above: unless you're very clear on what exact firmware versions you have loaded on the various radio bit on your iPhone, steer clear.