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](http://android.stackexchange.com/q/3190/15) 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](http://www.appbrain.com/app/dolphin-browser%E2%84%A2-hd/mobi.mgeek.TunnyBrowser) for example, the "www" isn't there so typing "android.stackexchange.com" works fine.