please follow below steps:

1. Click "Plugins" --> "Manage Plugins"
2. Search "Georeferencer GDAL" in the Filter and Enable the plugin by tick the box
3. Click "OK"
4. Click "Raster" and you are able to use the Georeferencer Tool.

It seems that QGIS need to load each external plugin so you can find it in the menu bar. http://docs.qgis.org/html/en/docs/user_manual/plugins/plugins.html#load-core-plugin

please follow below steps:

1. Click "Plugins" --> "Manage Plugins"
2. Search "Georeferencer GDAL" in the Filter and Enable the plugin by tick the box
3. Click "OK"
4. Click "Raster" and you are able to use the Georeferencer Tool.

It seems that QGIS need to load each external plugin so you can find it in the menu bar.

http://docs.qgis.org/testing/en/docs/user_manual/plugins/plugins.html#load-core-plugin