This video tutorial by photographer Nathaniel Dodson (from the website tutvid) looks at tracking an object in Premiere Pro both manually and automatically.
The most powerful tracking functions are still found in Adobe After Effects but if for whatever reason you rather use Premiere Pro than this is what you need to know.
Adding tracking manually can be a lot of work (depending on how accurate you want to be, how long the tracking section is and how much movement there is). The process itself is pretty simple though – you have to create keyframes and make sure that you keep the subject in those keyframes where you want it to be (basically tracking the subject with each keyframe.
This is pretty laborious work but not a very complex one. The automatic part that Dodson shows in this video is a little bit different. From what we understand it relays on the already existing tracking done in the previous part and just follows it (in this case by adding a mosaic effect (try this for yourself and see how it goes.