Help! Unlock and jailbreak Iphone 3GS 4.1?

[Robert]

Hello,
I have recently purchased an Iphone 3GS running iOS 4.0.1. My service provider is Claro Puerto Rico. I wanted an Iphone 4 but they were too expensive so I got a 3GS off Ebay. Puerto Rico is a United States territory so AT&T is the only Iphone carrier here. I don't want to leave my company, but I do want an Iphone.
I would like to update to iOs 4.1, however I have read up and watched videos on youtube and am still not clear on the subject.
Here are my questions:
1) Do I need an AT&T sim card to jailbreak with green poison or lime rain? How do I jailbreak? If I do NEED a sim card can I just buy a prepaid AT&T sim at Radio Shack and use it for the jailbreaking process?
2)How do I unlock the phone after jailbreaking?
I would be very grateful if you could include step by step instructions as well as answers to my questions and any download links that may apply.
Thank you very much!!!!
Please no ludicrous answers!!!! The person who sent the answer below must have trouble reading! I have read up and watched videos on Youtube! I need to clarify those 2 questions. Thank you

[vicecaptain]

Let me make it clear. If you want to use Claro network on an AT&T network locked iPhone, It has to be unlocked from network restriction first. It is not necessary that you should jailbreak an iPhone to swap network. Just unlocking is enough. You can unlock your iPhone safer and easier using Remote Unlocking Service. This method of unlocking doesn't require a jailbreak as it is a permanent unlocking. You can get the remote unlocking service for an iPhone model from Onlinegsmunlock.com at affordable cost with easy unlocking guide. Good luck mate.