Techniques for using billing services to manage a personal address book are provided. The techniques comprise receiving a call detail record (CDR) for a plain old telephone system (POTS) or a voice-over-IP (VOIP) call by a user. The CDR is created by a telecommunication carrier that routed the call. The CDR may be stored on a telecommunications server associated with the telecommunications carrier. Address information for the call is determined from the CDR. This address information is added to the personal address book for the user. This address information may be available for the user when using an IM client.