Sorry i'm new to this

[Soxfan20000]

i have a 3GS and want to download apps that require the iphone 4

how can i updgrade my 3GS to be 4.0 compatible?

[i.Annie]

You mean they require you to be on iOS 4? Well first of all, do you have a Mac or PC and do you need to maintain an unlock?

[Soxfan20000]

i have a pc

i don't know what you mean by lock/unlock

i want to download Iphone 4 apps but it says my iphone is not compatible

[i.Annie]

Ok do you need to use your phone on another carrier besides AT&T?

When you say you want to download apps for iPhone 4, do you actually mean the apps are made only for the iPhone 4? Or do you mean you want to use apps that require your phone to be on iOS 4.0? because if you keep saying the app is for iPhone 4, obviously you're gonna have to go and buy an iPhone 4 then. If you're talking about iOS 4.0 and up, then you'd upgrade your phone to iOS 4.0 or up. But in order to help you do that, I'd need to know if you need to maintain an unlock or not (like I said, unlock means to use it on another carrier).

[SepticTank]

i have a pc

i don't know what you mean by lock/unlock

i want to download Iphone 4 apps but it says my iphone is not compatible

Put more simply-- iPhone 4 is the latest phone....which you don't have.

ios4--means operating system. Your 3GS shares the same iOS with an iphone4.

So you are asking about iphone4 apps but almost all of them are interchangeable since they share the same iOS (operating system).

Annie is saying (do you already have a contract with AT&T? If so, you don't need an unlock. It's meant for others who want to "unlock" it and sign up with a different carrier.

With these clarifications in mind, re-ask your question

Jon