Google is currently testing a new search home page with bigger search buttons, brighter colours - bold white typeface on bright blue - with a slightly different logo, one without the shadows.
The search giant is also introducing one sidebar on the left that replicates the permanent top menu bar, something that has been tested for sometimes in its Google Labs in the form of Search Experiments.
You might need to log out from your Google Account to get it to work and some users outside the US will need to use the Google NCR (No Country Redirect) command to go to Google.com. Other services like Google Maps or news still use the old user interface.
Furthermore, the new design - which some have likened to the new Google Wave scheme - allows users to focus on results in certain periods and provides with related search strings, something that was, until now, pushed at the end of the SERP.
Google's decision to update its SERP look might come from the fact that new search engines like Microsoft's Bing and Yahoo have successfully brought in significant changes to their SERPs without alienating their users.
This is a limited test and it is likely that Google will choose to roll these updates very, very carefully. We're not sure how people will react and whether it might have a significant impact on the number of people actually using the website. Google is notoriously conservative when it comes to its front page. Apart from the occasional logo swap, it very rarely modifies anything else.