http://www.google.com/search?q=test
Obviously, you should replace "test" with your query. If there are multiple keywords, replace space with "+" like this:
http://www.google.com/search?q=test+my+speed
You could drop "www." from the URL:
http://google.com/search?q=test
Google now uses AJAX to load search results, so you can replace "search?" with "#":
http://google.com/#q=test
You can even drop the slash after "google.com" and the URL works in most desktop browsers, but not in mobile browsers. You could also replace "google.com" with "google.ca" or other Google domains, but you'll get different results.
Fortunately, Google owns the googl.com domain and you can use this URL:
http://googl.com/#q=test