SOGo is a very fast and scalable modern collaboration suite (or groupware). It offers calendaring, address book management, and a full-featured Webmail client along with resource sharing and permission handling. It also makes use of documented standards (IMAP, CalDAV, CardDAV, etc.) and thereby provides native connectivity (without plugins) to many clients such as Microsoft Outlook, Apple iCal, the iPhone, Mozilla Lightning, and a plethora of mobile devices via SyncML. It can reuse any existing email and database infrastructure, avoiding long hours of site restructuring.
Address Book Server allows you to share your contacts and calendar events with others connected to your network or over the Internet. Each participant synchronizes their contacts with the server hosted on your own system. Address Book Server supports the full Address Book and iCal schema. The server also provides a friendly Web interface and an iPhone client which let you access your contact details remotely.