An interesting side effect of Google Notebook's integration with Google Bookmarks is that you can now bookmark search results without having to install plug-ins or use bookmarklets. When you log in to a Google Account, a new option appears next to each search result: "note this". If you click on "note this", Google will open a small version of Google Notebook and add a link to the search result, the title and its snippet as a note. Google's service has a predefined notebook that stores bookmarks (Unfiled bookmarks), so Google also creates a bookmark from your link.
The only thing you need to do before clicking on "note this" is to make sure that the active notebook is "Unfiled bookmarks". You can click on the "My Notebooks" link from the top of Google's search results page to activate that notebook.
After bookmarking a page, you can add labels and comments. The bookmarks can be accessed from Google Notebook's mini-window, Google Bookmarks or from an iGoogle gadget, but also from plug-ins like Google Toolbar.