Here is our video on how to unlock iOS 4.2.1 baseband 05.15.04 & iOS 4.1 baseband 05.14.04 using Ultrasn0w 1.2 on iPhone 3G & iPhone 3GS. The video will give you walk through the entire unlock process along with links to our Ultrasn0w 1.2 unlock guide & Baseband update video in description.
If you are finding it difficult to follow our step by step guide then this video is for you. If you have any questions or query you may ask in Youtube comments section or comment here.