Yay! Whilst IE was steadily improving and although there are a lot of “alternative” browsers, this is the first one I guess that is actually not simply a different IE wrapper. It’s Opera Mini! Whilst yes, ideally it would have been Opera Mobile, at least it’s new.
Their test version is available and they want to give you the best browsing experience on your Windows Phone. Opera mini compresses the information before you view it. Great for a slow connection or limited bandwidth (e.g. Nokia Xpress browser).