Just last month around this time, we had posted a screenshot tour of the new search interface Google was experimenting. Now, Google has gone ahead and with that interface and has planned to get it hardwired into the design.
That would mean, we will see this design by default on the Google search from now onwards. You can see the post made on Tuesday, 13th Apr 2010 here. It has a comprehensive list of changes to check out.
The new search interface has a better interaction with results from live social activities. This is being managed by redesigning the left sidebar which scales in behavior depending on the type of content searched for. Google has laid a lot of stress on segregating search results categorically and relevantly with this sidebar.
The search results page looks a lot cleaner and this new design which has already been implemented will be continuously improved. The change will be applied over a period of 48 hours, so do not panic if you cannot see the change right instantly.