http//map.ubuntu-be.org is basicly what you described, and more. It's been running for about a year now, and a great success. It's only been a few weeks we have moved to a decent codebase, written by Pierre Buyle and accomplices.
Why did we use php? Maximum collaboration. Easily installed onto about any other server. Easy for you to contribute.
You're more than welcome to contribute:
Update: For clarity's sake: map.ubuntu-be.org is only serving Belgium right now. In response to this post, there have been several requests to open it up to other parts of the world. That sounds like a good idea. Some thoughts:
Three things necessary for opening up map.ubuntu-be.org beyond Belgium:
- Some localisation and performance improvements. Most of the localisation is done, but a few strings here and there are still Belgium specific.
- The locoteam for your region (if any) should support the idea. If there's no locoteam for your region, a map like this is a great way to bootstrap one. That's how many Belgian team members got involved.
- Someone to bootstrap and maintain your region of the map. A big word for little work, but it needs to be done. Things like
- adding zoom areas for cities in your region to the map
- answering questions by local volunteers
- some elementary quality control