When does google updates its search engine results. I am little confused in monitoring rankings for my sites targeted keywords. Everytime I check, i am noticing fluctuations. I need your views

There's been a lot of discussion around the boards concerning bouncing around in Google over the past of months, folks being hard pressed to find a lot of rhyme or reason in the results. It also appears that Google did have some sort of update on or about June 3rd. You should take a look a this thread (http://forums.searchenginewatch.com/showthread.php?t=22784).