This plugin allows you to have multiple blogs running off one WordPress install which can share content, have different titles, descriptions and theme
Unfortunately, this plugin is very experimental. The version number shows how far it has come since the beginning, not how well it works. It taps into every part of WordPress and modifies it. There are guaranteed to be bugs, which is why I suggest it for developers only.
For the most part I don't support conflicts with other plugins. However, you may report which plugins work and which ones don't.