Did you know you can access your computer using your smartphone? I have been in situations where I needed to print a document at Office Depot, but I forgot to email the document from my home computer. It would be a waste of time and gas to drive back home to the email document. Fortunate for us, there are a few different remote desktop apps such as real VNC and Splashtop that allows us to remotely access our computer, as if you were sitting right in front of it.
For most apps, all you must do is download the app on your phone and computer and connect the two devices.