From Android Market:
Secrets for Android securely stores and manages passwords and secrets on your Android phone.
See code.google.com/p/secrets-for-android for user’s guide.
1.4.9: Important fix for lost secrets issue, performance improvements when waking phone from sleep mode, minor tweaks to restore dialog
was developed for Android by Roger Tawa Jr
System permissions : This application doesn’t need special permissions
Very simple but does its job and seems very secure, forcing you to retype your password when the phone sleeps, when you enter/exit other apps, and more. If you’re looking for details, there are a ton more at the Secrets for Android Google Code Page.
[Via Twitter, UnwiredView]