One of my favorite jailbreak iPhone apps for iPhone OS 3.x.x was Lockdown, which gives users the ability to password protect their iPhone apps.

ipodtouchmaster, developer of Lockdown has released Lockdown Pro, which is compatible with iOS 4 or later.

But it is no longer free. It costs $1.99 on Cydia or Rock Your Phone store.

Lockdown Pro comes with the following new features:

• No extra application for Lockdown Pro’s settings. The settings are now available in iPhone’s Settings Application.

• No respring required.

• You can choose between alphanumeric or numeric passwords.

• You can setup different passwords for individual applications.

• Delay lock feature, which is a useful feature. If you unlock an application, it will also unlock other locked applications until you lock your iPhone.

• It also includes graphic, speed and stability improvements.

The developer is planning to soon release a new version, which will include the following new features and enhancements:

• Ability to lock folders, one of the major features introduced in iOS 4.

• Ability to lock and unlock an app from the SpringBoard, which currently needs to be done via the Settings application.

• Improved graphics.

You can also checkout Locktopus, which  is another app that is available on Cydia that also allows you to password protect your iPhone apps. I switched to Lockdown Pro after using it for couple of days as Lockdown Pro automatically launches the locked iPhone app after entering the correct password, which is not available in Locktopus.

As always, please don’t forget to give your feedback in the comments section below.