You can make it "look" like HTC SenseUI by using a variety of apps (homescreen replacement programs, widgets, etc). If you want it exact, you would have to root your phone and install a custom rom that has Sense UI on it. There is currently a custom rom with Sense UI running on Android 2.1 that works on the Droid, but just barely. Many, many things are broken on it, so it's not worth trying at the moment...