I'm not the most up to date when it comes to being tech savy, and I need some help!

Recently, I purchased an unlocked/jailbroken Iphone 3GS on Ebay. I got it and it works fine. I don't use it enough to make it worth paying for a monthly plan, so I just use one of AT&T's pre-paid Go-Phone cards in it and I pay a little extra to buy data time so that I can use internet features and apps.

Now here's my problem. I primarily got it to use Apps such as Flightaware's, when I'm out spotting. When I got it, it had Apple IOS 3.1 software on it. So far, anytime I've tried to download a new app, such as Flightaware, it tells me the app won't work until I upgrade to IOS 4! I started to to do this and got halfway through the process when I read online that if you update the IOS version on an unlocked/jailbroken Iphone, it will once again be locked and unusable to me!

It seems like every app I've tried to download has required IOS 4 or newer! Therefore, I can't use Flightaware or any other apps I got it to use with! I don't know anything about unlocking/jailbreaking Iphones, so I'm resistant to upgrade to a newer OS in fear that I will find my phone once again locked and useless!

Help! What can I do? When I bought this Iphone I didn't know anything about the Apple OS, nor did I realize that most current apps require IOS 4+. How can I upgrade to IOS 4+ so that I can actually download and use current apps without having my phone relocked? If that happens, I don't have a clue how to go about getting it unlocked/jailbroken again! That's why I specifically purchased one that was already unlocked!

Surely I'm not the only one who's has this problem? Yet, I can't find anything online concerning the problem! God, I hate the mobile industry in the USA with the way they lock their phones to provider it was originally purchased from.