Hello,
Some years ago I wrote an application that would take 3 items: lat/long and a radius. It would then return the names of all locations within that radius. Locations are currently other cities and towns (works or should work world-wide), but expandable to other stuff if you have the data. Everything is done in memory so its fast.
I have since moved on to other stuff, but if it helps someone who's been left in the lurch by SimpleGeo's unfortunate demise I can make it available in a few days.
Free unless traffic for the service interferes with my current project.
If you're interested drop me an email.
