Steps to Lock Application in your android phone using password
Go to the Android Market.
Search for “Perfect App Protector” by Morrison Smart Software.
Install Perfect App Protector (Its Free!)
Launch the App and type in the default password (7777).
After successful login, your first job is to change the default password. tap ‘Settings’ on the screen and scroll down to find ‘Chang Password’, tap to register a new password.
Tap on “ALL” from the application to Pick Apps that you want to password protect (Text Messaging, Email, Voicemail, Market, etc) and touch the lock button. You’re done.
From now, whenever you try to open the messages application, the password should be entered to see the texts.
A normal question that would arise in your mind is “What if someone uninstall the application?”. The app developers considered this a s a chance and pre-locked the package installer in android so that no application could not be uninstalled without password. Make sure that Auto start is enabled in settings to restart the lock service when phone is restarted.