The underConstruction plugin allows you to put up temporary page that users who are not logged in will see. You can use this to build a site live, that can only be viewed by users who are logged in, while others will get the ‘Under Construction’ page during construction
important note about WP 3.0
As of version 1.04, underConstruction supports the 3.0-alpha release. As we get closer to the release date, I’ll continue to test, but it appears that this will work great on single-site blogs ONLY.
Multi-blog users, read on. I’m thinking about building in support for the Network feature of WP 3.0 but it’s not worth it right now, due to the ridiculously sparse documentation and the fact that I’m not sure if anyone would actually use it. If you’re a multi-blog user who REALLY needs this to be available, sound off in the comments so I know this is important to you.
Questions? Leave them in the comments, and I’ll get back to you asap
If you like this plugin, please rate it at wordpress.org! http://wordpress.org/extend/plugins/underconstruction/