GD Press Tools
Maintenance Mode
Maintenance mode is very useful addon allowing you to leave your website online while doing some work on it, but to display a message about ongoing maintenance and inform your visitors about expected downtime.
What is great about the way this works, is that you have a lot of customization settings: you can add logo, format title, add content into page header or footer area, include customized messages and estimation of downtime or simple counter.
The plugin uses templates system to display the mode message, and it includes 2 default templates, but you can add more through your theme and customize it to look like your theme.