We've been using a great new cross-platform tool to hide sensitive data from prying eyes. Even if the feds come and hijack your disks, they'll almost certainly never get to your most-private information (membership lists, action plans, etc). The application is called TrueCrypt, and like the JPasswords application we recommend for password storage, it runs on Java (which means Mac, Windows or Linux and great portability). Also, it is ingenious and works really, really well. If you use it properly, your sensitive data will never even be discovered -- and even if it is, prying eyes will find it nearly impossible to break the encryption. LifeHacker has some great advice on how to start using TrueCrypt.