What this module does
This module provides ability to customize text messages on OpenMRS web pages and persist them within database table. Also this module provides default export feature that allows you to choose from the list of available locales and export all existing messages (both those that came from the properties files and those customized by the module). So you can just export the messages in a locale, this will construct a file called messages_xxx.properties, and you should just be able to take this and replace the appropriate one in core.
Documentation / How-To
It took a slightly different approach of messages loading and overwriting than Database Messages Module. Within this module the original messages.properties files are retained as the primary message source, and the messages stored in the custommessage module tables can override these values. So only customizations made by an implementation are stored in the custommessage tables. This means that if core or module message.properties are changed and re-uploaded, these new values will be used unless they have been explicitly overridden. And it is easy to see exactly what has been changed and what is standard.
Downloads
https://modules.openmrs.org/modules/view.jsp?module=custommessage
Screenshots
With this module you can easily customize text message by its code. Everything you just need is to select (or filter) interested message by code in left side panel. Right side panel will contain all available variants of this messages for currently supported locales with ability to customize this. 
To change exact message just click on Edit button in message panel, enter your text, and press save. Changes will take effect immediately, no restart needed.
Also you can filter messages by code or text using Manage Messages page.
This module provides default export feature that allows you to choose from the list of available locales and export all existing messages (both those that came from the properties files and those customized by the module).
Release Notes
1.1
- Initial alpha release
About
This module was developed by Mike Seaton.