Addresses is a GNUstep address book that consists of a full-featured address book manager application, a source-code compatible replacement for Apple's AddressBook.framework (for accessing and manipulating address data programmatically), a framework of view/editor classes that make it easy to use Addresses from your own programs, and a number of tools. It is easy to use by both users and programmers and can store almost all imaginable data, including multiple phone numbers, emails, and addresses, photos, AIM/Jabber/ICQ/Yahoo IM details, and notes. It supports drag-and-drop and integrates well with GNUMail.
AddressBook X LDAP provides a shared addressbook on your local network, without the burden of subscriptions. It is an iSync enabled application which transfers contacts from the AddressBook to a central LDAP directory. It also provides the ability to browse and search the directory. Multiple schema mappings are available and can be customized and extended to address individual needs. Currently, ABxLDAP Person (an extension to InetOrgPerson) is fully supported, but the Mozilla Schema and the basic InetOrgPerson are in development. Support for Active Directory is included as well.
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.
ZEG, which stands for "Zero Effort Groupware", is a virtual appliance of SOGo intended to provide a complete out-of-the-box testing environment. SOGo is a collaboration suite (or groupware) with speed and scalability in mind. 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 (CalDAV, CardDAV and GroupDAV, vCard, and vCalendar/iCalendar) and thereby enables the use of many clients and the reuse of any existing infrastructure. The appliance is prepared to be imported in VirtualBox but can also used in VMWare.