A system, method, and computer program product are provided for conveying availability information of a calling party to a called party. A PBX serving the telephones of the calling and called parties is connected to a presence server. In an embodiment of the invention, the presence server is also connected...http://www.google.com/patents/US7957514?utm_source=gb-gplus-sharePatent US7957514 - System, method and computer program product for conveying presence information via voice mail
