we map flickr
Well, not 'we', that should be 'you'. I'v quickly thrown together a google/flickr mashup where, on a map of the world, you can see links to pictures from specific places. The map comes from Google, the pics come from flickr.
What's more, you can add your own places, assuming they refer to a flickr tag.
Not making sense? Check out Google local, flickr and we map flickr (since taken offline).
The issue with putting cities on a map of the world is getting high quality geocoded city names. This is the reasons that, so far, I've only managed to put up some 7 countries. More will follow, however.
On a side note, I stumbled upon a very lovely collection of pictures here and a great flickr implementation here.