Guys need some help regarding 3gs, i have never used ios. I am buying 3gs 16gb. 1. How do I check before buying whether it's factory unlocked or not? Also how do I check the baseband and which baseband should I avoid? 2. After jail breaking, can I visit the apple app store from my mobile? 3. When updating/changing firmware can I backup all my installed apps? 4. Is it possible to roll back to ios 4 after trying ios5?? 5. If my phone is factory unlocked then I dont have to worry about phone getting locked when upgrading etc right? 6. Which IOS4 version do you recommend for 3gs?