Is There an App Locker in App Store for iPhone 4?

Hello Becky, I don’t think that there’s an app locker available in iTunes App Store. But if you really want to get an app locker, then maybe you should consider jailbreaking your iPhone as there are numerous app locker available in Cydia Store – an alternative App Store for jailbroken iPhone, iPad, and iPod Touch.

If you want to jailbreak, I would recommend to jailbreak your iPhone 4 on iOS 4.3.3 using Resdn0w 0.9.6rc16. But before restoring or jailbreaking, you should perform a backup first to save all your data and restored it on your iOS device once jailbroken and restored. You can download the stock iOS 4.3.3 from here and the download link for Redsn0w 0.9.6rc16 is posted here. You can follow this tutorial on how to jailbreak iOS 4.3.3 on iPhone using Redsn0w.

Once jailbroken, just simply launch Cydia app and download Lockdown Pro 2.0.3 under BigBoss repository and install it on your jailbroken iOS device (iPhone, iPad, or iPod Touch). Lockdown Pro 2.0.3 features a very easy to use interface and offers a stringent and easy to configure password protect security for your iOS and jailbreak apps. To lock and unlock an app, just simply hold down the app icon to get into wiggle mode, then click the little lock icon on the bottom right corner of apps or folders to change that app to lock it or unlock it. Lockdown Pro 2.0.3 also gives you an ability to password protect your apps and folders and you can choose between alphabetic or numeric password. Hope this helps.