I love that people share (give away) useful stuff they have made on the web. Morten Just has created a set of stencils for web designers that can be used in Google Docs.
If you need to prepare some wireframes this might be an option for you. I have previously mentioned balsamiq mockups which I like very much as an alternative. This Google Docs option means that wireframes can be created collaboratively.
If you create more stencils you want to share contact Morten and they can be added to the shared folder.