Just Released: Have I Been Pwned?
I just released Have I Been Pwned? to the Windows Phone store. It's a tiny, tiny app that only took me a couple hours to build. You can find the source code on GitHub.
HaveIBeenPwned.com is a website created by Troy Hunt, a security MVP, that checks to see if your email address appears in a database of all the breached email addresses in prominent hacks like Gawker, Sony, and Adobe. I've definitely been pwned, so it's a good service to use to quickly see if you need to change your passwords.
I plan to add the background task soon but I wanted the initial release out there so that I can just submit updates to it. If you want to contribute, send me a pull request!