Easy, just do a screen capture of the Google map view you want to use, save as a jpg, and use that image as the map image for your tour. I do not know what Google's terms of Service are, make sure your not doing anything that violates anyones copyrights and you should be good to go.
Had a look at that www.krpano.com site and it has some very nice features. I guess the GUI is not as user friendly as TW but some of the hotspot controls and plugins are awsome. I hope TW takes a look ;)