For Word and PowerPoint 2011, templates are stored inside your home folder in ~/Library/Application Support/Microsoft/Office/User Templates/My Templates.
How to get there ????
Since "Library" folder is hidden in Lion, you can go there by the following
1. Click "go" from the menu in Finder
2. Select "go to Folder ... "
3. Enter "~/Library"
4. Click "go" by holding down "Opt/Alt" key.
Then the "Library" folder will show in the Finder window.