2. Evernote

For iPhone: itunes.apple.com
For Android: play.google.com

I only recently discovered this app for iPhone, but was a huge fan of using it at work on my PC. The app is even better! You can store to-do lists, notes and reminders for events and just generally stay organized. It’s also a handy app for noting down things from your day – payment authorization codes, receipt numbers, last-minute work orders, that cute guy’s phone number…