Umm... Sunny1211993, you might want to ignore iMav's advice. He hasn't ever unlocked an iPhone or even used it properly.
Updating via iTunes will
not brick your phone. Don't worry.
It will, however, re-lock it, so you'll have to unlock it yourself. The best way to do it is to use the iPhone Dev Team's PwnageTool. Just follow the clear instructions out here and you should be good to go: *www.google.com/search?hl=en&q="[PwnageTool]+FAQ+and+How+To+Guide"&btnG=Search
Let us know if you have any doubts.
Congratulations, by the way, on entering into the super elite iPhone club. 8)
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In related news, I dropped my iPhone from the height of about four feet onto a thin layer of dirty water today and, thankfully, it escaped unscathed. The back got dirty but after wiping it off, it was as clean as new. I was listening to music and there wasn't even a slight pause or anything on impact. It looks fragile but I guess it's not.
