A small personal project I've occasionally been working on is "Encrypted notepad" - a simple (really simple!) Notepad-like text editor whose only distinguishing attribute is that it saves and loads strongly encrypted files. Now, I have an Android version too :)
The original purpose of enotes was to share sensitive data in our office but there are a million uses for it - from storing secret barbecue recipes in it to using it as a simple free-form password manager. It is a Java application and is tested to run on FreeBSD, Linux and Windows (Sun JRE 6 and OpenJDK JRE 6).
The Android app is my first attempt at developing something usable for Android and I'm pretty satisfied at how it went. The platform is not nearly as weird as some older mobile platforms (Symbian, Java ME) but it still has plenty of "odd" choices to guarantee developer fun (what? you mean to tell me that on this multitasking platform I have to destroy, create and manually repopulate my UI widgets (form fields) every time the user switches between apps? was one of my favorites).
The Android app will eventually find its way into Android Market, probably as soon as I resolve some registration issues with Google. Until then, use the links provided above or this: