Earlier, iPhone Dev team have released jailbreak tool RedsnOw 0.8 for iPhone 3G S users and now they have also released UltrasnOw 0.8 to unlock iPhone 3.0 OS on iPhone 3G S.
The UltrasnOw 0.8 unlocking tool supports Purplera1n as well as RedsnOw. You can choose any of them to jailbreak your device, but I would recommend you to use RedsnOw 0.8 as it’s developed by popular iPhone Dev team.
Unlocking an iPhone 3G S is very simple and anyone can unlock it within few minutes. Here’s the guide to unlock iPhone 3G S with UltrasnOw 0.8.
Note: This guide is exclusively written for iPhone 3G S. Don’t try to use it on other devices.
Guide to Unlock iPhone 3G S OS 3.0 with UltrasnOw 0.8
Requirement:
Steps to follow:
- Open Cydia on iPhone.
- Insert repo666.ultrasn0w.com repo in source and select ‘Add Source’.
- Press ‘Return to Cydia’ and click on ‘Done’.
- Select the UltrasnOw repo in Cydia and install UltrasnOw 0.8.
- After successful installation, restart iPhone 3G S.
Now enjoy your unlocked iPhone 3G S with iPhone 3.0 firmware. 
You can also watch following video to get an idea about iPhone 3G S unlock.
[...] Guide to Unlock iPhone 3G S OS 3.0 with UltrasnOw 0.8 [...]
[...] 9 – open up Cydia again and follow these instructions to install Ultrasn0w. Once installed…restart the phone and you should be [...]
[...] Guide to Unlock iPhone 3G S OS 3.0 with UltrasnOw 0.8 [...]
[...] Follow the same steps mentioned in UltrasnOw 0.8 guide. [...]