Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.

Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...

TaskBoard - A Kanban-inspired app for keeping track of things that need to get done.

TextMe - TextMe is a free calls and messaging application at both local and international levels.

LeanKit by Planview - See how Planview LeanKit enables engineering teams across all levels of the organization with a visual work delivery tool to apply Lean management principles to their work, helping them work smarter and deliver faster.

Talkatone - Android App on. Google Play. Stop paying for cell minutes, texts & landlines; Turn your iPad or iPod touch into a phone; Call/Text even in areas with bad cell coverage; Call/Text when travelling without paying for expensive international minutes.