You can now use the up/down/left/right arrow keys and the Enter key to quickly navigate through and select from Instant's ever-changing list of search term options.
It's kind of a no-brainer enhancement, but it's a feature that speed freaks (that is, those whose lives and online searches are optimized for fewer mouse-clicks and faster results) are sure to appreciate.
Another new item is Instant's expansion into Google's left menu of search options. That is, you'll get Google Instant results when searching for News and Video searches just as you would with general web searches.
Here's a brief demo video explaining how Google Instant's keyboard navigation works:
On the international front, Google Instant is also rolling out to Austria, Belgium, Canada, the Czech Republic, Ireland, Mexico, the Netherlands, Poland, Slovakia, Slovenia, Switzerland and Ukraine. Previously, the product was only available in the U.S., U.K., France, Germany, Italy, Russia and Spain. Instant should be coming to even more countries within the next few weeks.