1. A communications system comprising: a first server having an electronic mail (e-mail) database for managing e-mail accounts, for storing radio device addresses associated with those accounts, and for storing electronic mail messages associated with those accounts wherein each message has a header and text; a gateway connecting the first server to a two-way radio network; a radio device having a electronic messaging application, the radio device comprising a message generator and transmitter for generating a command and transmitting the command to the server over the two-way radio network to request a further portion of the text and being capable of two-way communication over the two-way radio network; wherein the first server comprises message handling software arranged to send, to the radio device, a portion of a message of a user-selectable predetermined size, including a header portion and a text portion, the first server further maintaining a database of e-mail messages associated with e-mail account identifiers and the radio network comprising a second server maintaining a database of paging messages associated with pager addresses, and wherein the first server maintains a table correlating e-mail account identifiers with pager addresses.