Softros LAN messenger - LAN messenger for an internal office chat for home or business users. It does not require a server and is very easy to install and use. It supports personal chats, group chats, message brodcasting, files transfer and remote desktop access.
HostsMan - HostsMan is a freeware hosts file manager and editor. Built-in hosts file updater
MyChat - Secure instant messenger for any network
Gas Mask - Gas Mask is simple hosts file manager for Mac OS X.
BORGChat - BORGChat is a LAN messaging software program.
SwitchHosts - Free and open source hosts management & switching app