No offence, but aren't you six years late on this? This looks like one of the hundreds of startups launched in 2004 with the idea of "Put pins on a Google Map and save it in a database". Lots of those startups got funding for it, and they've all run their course. Since the functionality you're planning to build is now actually built into Google Maps itself, what's your purpose with this thing? From an implementation…
Agreed, this seems to overlap completely with Google Places: http://www.google.com/lbc