Enfomi is a cross-platform standalone password-based encryption/decryption program that supports 27 algorithm variants (including AES 256bit). Archives can be self-decrypting, thus making it perfect for mobile applications.
Amnesia is a design-rich 'host-proof' web application that encrypts and remembers all sorts of personal information from passwords to private notes. Project now hosted at Google Code: https://code.google.com/p/amnesia-app/