"The Google bar, which runs across the top of the browser of nearly all Google services and offers easy access to Google's products, has recently updated its look for a more consistent, streamlined user experience and increased visibility of the most popular services," explains Google.
The new navigation interface no longer uses additional space, it's more compact and the short list of Google services that's displayed by default matches Google's simplified product line. The menu links to Google+, Web Search, Image Search, Google Maps, YouTube, Google News, Gmail and Google Docs, but you can mouse over "More" to see additional services. Here are the services that have never been included in the navigation bar until now: Google Wallet, Google Offers, Google Music, Google Mobile and Blogger.
While the new interface looks modern, it's also less user-friendly because the navigation links are hidden behind a drop-down menu and the average user might not be able to find them. Android's menu button wasn't a great idea and Ice Cream Sandwich made menus more visible, so it's not clear if this is going to work. Google's homepage will expand the product menu by default, but it will be interesting to see if Google users will actually notice that mousing over the Google logo lets them access Gmail, Google Docs and other services.
I don't see the new interface yet, but it's likely that it will be rolled out in the coming days.
Update: try the new interface.