On those Windows machines with Skype installed, it tends to convert all phone-formatted numbers to Skype links so you can click it in order to make a call on Skype.
If you are using PhoneGap on iOS this can be a UIWebView issue (separate from Skype).
The following line fixes the problem if you don't want automatic links generated in UIWebView:
self.viewController.webView.dataDetectorTypes = UIDataDetectorTypeNone;
inside AppDelegate.m in -(BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions