Google has been testing filters in the for some time now and now it seems to be available on the desktop search interface.
Sergey Alakov posted about it on Twitter last week, his filters show on the left side but I see a filter on the left and a sort on the right.
Here is my screen shot showing filter by hours on the left and sort by relevance or distance on the right:
Here is Sergey's screen shot showing both on the left:
It does seem like these filters are fully live now.
Forum discussion at Twitter.