The first step is to install Google Earth on your computer—it's new, improved 3-D renderings of New York City, especially, are a goldmine for architecture buffs, who can sync it with the American Institute of Architecture's 150 greatest-hits layer for hours of voyeuristic fun.
If you find Google's 3-D renderings a little too cartoony (or creepy), or just want to get out of the big city, start experimenting with street addresses and the Google Maps "street view" function and/or Microsoft Maps' "bird's eye" view. This way, you can get away from the picture-postcard views of interesting architectural sites and see what the houses look like in situ. For example: Here's the official real estate listing for a Frank Lloyd Wright house currently for sale, with its dull "mugshot" photo:
but plug the address into Google and click on the street view, and you can see how the house is situated in its subdivision (and what kind of SUV the neighbor drives).
The possibilities are endless: Here's a list of Richard Neutra house addresses to get you started. Flying around the globe in search of roadside modern classics should provide hours of virtual fun during the long, cold winter ahead.