If a cellular phone isn't a smartphone (i. E., a Blackberry, iPhone Android or other windows mobile device), the easiest solution is to acquire a microchip, covertly attaching it to the inside of the phone. This way, the phone can be tracked anywhere and anytime. However, these aforementioned microchips can be quite pricey, but are available online.
If a mobile device in question is a smartphone, it is a lot simpler to trace. Aside from tracking, other information from the phone can also be accessed - text or SMS messages, phone calls and browser settings. All this information and more is stored online where it can be viewed whenever via access of a remote server.
It will be completely and extremely easy to locate a phone for free online discover who's been calling the mobile phone, and all outbound calls. It can note all messages: text or SMS. Some even have the option to record calls. The tracking software is also able to view all of the website history and e-mails that said smartphone encounters.
There are several types of mobile phone tracking software which is available to download online. Primary concern is to thoroughly read up on these, making a decision that most congeals with what one would like to happen. Be sure to note the type of smartphone that will be tracked, and its operating system, etc. There are some instances of tracking software that will be a lot better depending on the type of smartphone and also the operating system.