The Internetwork Mail Guide, recently updated, documents methods of sending mail from one network to another. It represents the aggregate knowledge of the readers of comp.mail.misc and many contributors from other sources. The Guide explains e-mail sending conventions between different combinations of many different networks. It is provided by Scott Yanoff. Also available is a forms-based service that lets the user enter the "from" and "to" networks and returns the proper addressing to get from one to the other.