WebDAV: Get address books of other users
First, use TElWebDAVClient.PrincipalCollectionSet() method to get the list of principal collections. Then you can call TElWebDAVClient.ListPrincipals() method for each collection to retrieve a list of principals at any depth. The method returns result as an instance of TElWebDAVPrincipalList filled with TElWebDAVPrincipal objects.
Each TElWebDAVPrincipal object has AddressbookHomeSet property, that may be used to get a list of address books for particular principal. TElWebDAVPrincipal.AddressURL property may contain an URL of principal's personal vCard, if this extension is supported by a server.