Beside promising to permanently unlock iPhone 4 Baseband 4.11.08, CutYourSim also offers to unlock on any baseband and any other device models. At the end, your device will be permanently unlocked to use any GSM carrier you desire.
CutYourSim is utilizing your device IMEI for unlocking, and it takes about 20 days for the unlock to complete. Why takes that long? It's simply because high demand for other iPhone 4 users to unlock their device.
And CutYourSim unlock tool works for iPhone 4s, 4, 3GS and 3G and on any iOS version plus any baseband.
Update: if your baseband 4.11.08 is AT&T iPhone, then you can officially unlock it and for a jailbroken AT&T iPhone visit this page to unlock it and keep your untethered jailbreak.
If you are interested, you can visit its homepage to study it more: here is their website. The link to the CutYourSim's website is removed, since the developer has stopped offering the service.
- Unlock iPhone 4s Baseband 1.0.11, 1.0.13, 1.0.14
- Unlock iPhone 4 Baseband 4.11.08 Is In Testing Stage