This just needs to be a free text, multi line field. I tried that for a project, using the Google geocode API. Worked OK, though not flawless. Users entered

This just needs to be a free text, multi line field. I tried that for a project, using the Google geocode API. Worked OK, though not flawless. Users entered their address into a textarea. This got passed off to Google, and the app then looked at Google's response. In case of ambiguity the user would be prompted to clarify the address and try again. The intent was to reduce crap in the application database, but at the same time we had to allow users to override whatever Google thought and provide a literal address.