Go! is a simple utility that aims to mimic the "Type address here" field as found on a Windows system coupled with Internet Explorer 4.x. Go! leaves a resizable floating window in the Finder that can be dragged anywhere. From there you simply enter a URL into Go! and you will be switched to your preferred browser (which will be loaded if necessary) which will the load the URL.
So why use Go! when an extension like ICeTEe, which many programs install, allows you to command click URLs to have them load in your browser? For one thing, if you decide to visit a site that just popped into your head, you can enter it into Go! rather than launch your browser and then want to enter it.
Go! may not be terribly convenient or much of a time-saver, but it's WhaterWare (send whatever you want to the author) which makes it worth it. Future versions will add the ability for Go! to access your browsers bookmarks, keep track of recently used URLs, and an option to force your browser to load the URL in a new window; all of which will make Go! considerably more useful than it is in its current form.
-MS