Without any application or software, it is just impossible to track your lost mobile phone. Nowadays, every smart phone there is a feature to track a mobile. A user may get it as inbuilt feature or he may get the same by downloading tracking application from the relevant app store. For instance, a user can download GPS based application which helps in tracking the location of mobile phone.
Use "Find My iPhone" via MobileMe. This is a free app, although you must have a subscription to MobileMe or an iPhone 4, iPad or iPod Touch 4G with the most recent iOS 4.2 updates, where the Find My iPhone feature of MobileMe is now free of charge. This method works on the built-in GPS chips, and can also be used to locate a lost iPad or iPod (via Wi-Fi in the case of the iPod Touch). You'll need to have MobileMe configured on your iPhone, and the Location Services feature will need to have been turned on on the lost iPhone (go to "Settings", then "General", then "Location Services").