Non app store apps for iPhone 3G I recently bought iPhone 3G from a friend, but i can't download apps from the official appstore because my iOS version is 4.2. Is there any website or even a way to install apps like facebook, without custom firmware like whited00r?
No, this is not possible. If an app requires a certain version of iOS, then you must meet that requirement, otherwise the app will not be able to be installed. You may be able to get hold of a version of the app that used to work on iOS 4.2, but it depends on the app.