I think that 'fronts', in this context, is related to frontage, (http://en.wikipedia.org/wiki/Frontage) the length of the property along a street and would only be used in this way when speaking about a building or property. In the northeast of America I do not see this often, but I would expect to see it in real estate listings (listings of properties for sale). The verb 'faces' can be used for anything that could be oriented in a specific direction. For example, I would say "He faces the computer.", "The sign faces east.", and "The room faces the garden", but I would not substitute 'fronts' in any of those places. The third sentence has the added meaning of "overlooking"; when I hear that sentence, I expect that I can look out a window in that room and see the road.

I have never heard someone say "The house fronts on/onto Main Street." in America. Although that may be a common phrase in other parts of the country but not in the Midwest!

Yes, to me they are interchangeable. Although to me 'fronts' is not a word I would use. Perhaps it is more American?