Using core location to see nearby friends?

[Theunodebruin]

Good day,

I'm fairly new to iPhone development and need some advise.

I want to develop an app that shows nearby people using my app. Something similar to google latitude / facebook event check in. I know how to get the users location but I'm stuck after that.

How will I know that there are people close to me? I'm thinking update the users location to a server, and display who ever is in the radius? But then I need a server for this? And query the server the whole time!? Is this the right way or I'm I missing something?

Any advise will be greatly appreciated!