maps.google rocks. I have been useing it for awhile. Only catch is, there is quite bit of land out there that doesnt have the info avaible for the 100% zoom. Alot of rurl areas and boonie lands only go so far. Which is kinda of bummer since alot of the railroads run through rural areas. Up side, in urban areas, where they have mor einfo, it can give you the map and satelite shots to find a good spot to watch.
Have a look at this site, the pictures are updated every few mins, you can see the international space station fly by at times and you can also see the hubble space telescope and other satellites flying by http://satellite.ehabich.info/index.html