Google Earth - Download it here!  It's Free!
The greatest thing about google earth is that in New York City area you can actually go down to street level and see a 360 degree view of what it looks like on the street.  I did this when I was apartment hunting for my daughter's first apartment.  Then we visited the apartment and I was very familiar with the street because I had already virtually been there on google earth.  So, this tool is a MUST for apartment hunting.

The program bogs down the computer sometimes and on some computers you may have to restart a few times, especially if your computer is old, but it is worth it.

To get the 3D Street View, open the google earth program and type in some New York City address.   If you don't have an address to put in, then type in the words Grand Central Terminal.  It will locate it and go directly to it on the map.  Now in the lower left area of your computer screen check off 3D Buildings, Street View, Borders and Labels, Roads, Geographic Web and Terrain in the check boxes.

Now look at the map and click on the little camera.  Let the computer zoom itself in and then you will see a little round vortex appear.  Wait.  It will open up a street view and surrounding areas.  You can go up and down the streets and turn yourself completely around by continuing to click the little cameras.  To turn around, hold your mouse key down until your cursor turns into a little fist on the computer screen then drag your mouse to the left or right.  It is an amazing feature and a lot of fun too!