Finally someone is putting out a complete linux alternative to Exchange and Outlook. Unison is the suite that combines IP telephony, e-mail and instant messaging with diary, address book and presence capabilities, all in a single Linux server. It is to be noted that users can get these elements separately as well.

Unison beta is released. Once the beta program is complete there will be a free “community” version for up to 20 users, and per-user or perpetual licenses will be sold for larger systems, although pricing for those is not yet fixed said Rurik Bradbury, Unison’s chief marketing officer.