This is a step-by-step guide to Install, Jailbreak and unlock iPhone 4.3.3. You may choose to jailbreak iPod Touch, iPad with the same method except leaving the options that are only available to locked iPhones. You should jailbreak factory unlocked iPhone with Redsn0w
Step 1: Collecting essentials
1.1] Select and Download required 4.3.3 OS stock firmware file from this download page . [If you’re on iPhone 3GS then you should choose ‘iPhone 3G S (4.3.3/8J2)’]
1.2] Download & install Sn0wbreeze 2.7 from this page
* Sn0wbreeze requires .NET Framework installed on Windows computer.
1.3] Download and install iTunes 10.2.2 (This is a must because it supports 4.3.3)
1.4] Take backup of iPhone data with iTunes.
1.5] If you have a jailbroken phone & Cydia apps installed on it then use AptBackup package from Cydia to backup application list.