I’m not sure if all Google sites based on countries have already Google Instant working on them. In my case, my country’s .ph Google site does not have Google Instant in it. When the feature was announced, I kept trying to see if any search results would appear while I was typing. Nada. Pissed and confused, I just ignored it.
Then came a thought. I thought I would try doing it while in the google.com site. Voila! It worked. If your Google’s URL points to your country’s region and Google Instant does not work, go to http://www.google.com/ncr where ncr means “no country region” and you won’t be redirected anymore.
Then you can use Google Instant freely ;).