I'm using this Beacon class to keep track of people who beta-test my iPhone and iPad applications.

The Beacon class simply calls a URL, sending some device and application information to the server. The following information is collected:

  createDate            date of the request
  ip                    ip address of the device
  deviceJailbroken      whether the device is jailbroken
  deviceIdentifier      unique id of of the device (UDID)
  deviceModel           model of the device ('iPod touch')
  deviceSystemVersion   operating system version (3.1.3)
  applicationVersion    application version taken from the Info.plist
  applicationIdentifier pplication identifier taken from the Info.plist
  hardwareMachine       hardware machine (N72AP)
  hardwareModel         hardware model code (iPod2,1)

The server side is a minimal PHP script that simply stores these values in a MySQL database. Both the PHP script and the MySQL script are included.

Example usage:

   Beacon* beacon = [[[Beacon alloc] initWithURL:
      [NSURL URLWithString: @"http://some.server.com/beacon.php"]] autorelease];
   if (beacon != nil) {
      [beacon signal];
   }

(The Beacon is retained by the NSURLConnection, so it is ok to keep it autoreleased, it will be dealloc'ed automatically when the connection is done.)