Spying and monitoring cell phones and tablets is quite possible through using popular tracking apps and software which are available on the market these days. MobiStealth is for example a great software to do the task. Just install it on the compatible gadget and it quickly work to collect needed info for later access by the subscriber.
It could enables users to spy on phone logs, email messages, text messages, calender, address book, etc. Also gps location tracking is allowed using this great program.
For more info look at the website mentioned above or just check the official mobistealth website which could give you plenty of data about how and why you need to use this app.