Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
LAN Messenger - LAN Messenger is a decentralized UDP IM-style chat client which supports usernames...
TextMe - TextMe is a free calls and messaging application at both local and international levels.
Softros LAN messenger - LAN messenger for an internal office chat for home or business users. It does not require a server and is very easy to install and use. It supports personal chats, group chats, message brodcasting, files transfer and remote desktop access.
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.
MyChat - Secure instant messenger for any network