Manually Installing a QGIS Plugin

See this website.
How to install python plugins in QGIS

Method 1 - manual install:

1. Close QGIS if it is open.
2. Unzip the file downloaded to your home/.qgis/python/plugins folder. Few other plugins folder should already be there.
         Under windows, 'home' is something like: C:\Documents and Settings\<user name>; where <user name> is your login name.
3. Restart QGIS, the plugin should now be available in the plugin list under the 'Plugins' menu 'Manage plugin...'.
4. In this list select the plugin (e.g. bcccoltbl) and click OK.
5. The plugin is now available in the 'Plugins' menu and on the plugin toolbar.

To open the qgis plugins folder right click on the qgis application and show package contents.

Update: In windows this folder is C:\Program Files (x86)\Quantum GIS Wroclaw\apps\qgis\python\plugins