It seems to be specific to the HTC Droid Incredible. When I first tried to search from the stock browser, I'd get an error page (I didn't notice the "http://www"). So I asked this question which gave some options in the form of browsers which are ready for search queries. (It turns out you can search from the stock browser once you delete the "http://www")
You may want to use another browser. In the Dolphin HD browser for example, the "www" isn't there so typing "google.com" works fine.