Many places on the globe have been photographed, street by street, by Google. Once you determine where your ancestor lived (look for addresses on censuses, city directories, or in other family history sources), just type in the place and let Google take you there. Look for the feature that allows you to "walk the street" (drop the little guy onto the road you wish to view).
Pretty soon, you'll be discovering whether or not your ancestor's house still stands, what kind of neighborhood it's in, and getting a feel for the area. How long would it have taken them to walk to the school or the church or the nearest market? How might things have looked different back then? So many discoveries to make, and all from your cozy spot on the couch in your pajamas!
Created with an image by WikiImages - "earth planet space"