LAN Messenger - LAN Messenger is a decentralized UDP IM-style chat client which supports usernames...
Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
Feem - Share files offline. No servers. No cloud. No limits.
TextMe - TextMe is a free calls and messaging application at both local and international levels.
BeeBEEP - You can message and share files inside your intranet without a server.
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.