We have a really great tutorial forum that could really help you out - not just with Parallax mapping, but also with other areas of game development. I really encourage you to browse and check out some threads. There's also a "Search" button at the very top of the page that will allow you to search this forum only. That way, you won't be redirected to random websites as you would with Google. Plus, this is what people refer to when they tell you to search for something :3
Here are two threads specific to Parallax Mapping:Parallax Mapping for Beginners
by SamGreenAdvanced Parallax Mapping
The second one has a video of Parallax in action.
The concept is really pretty simple. It's just like mapping through VX engine, only you have absolute control over the placement. Instead of a whole tile, you can place objects half a tile away, or even 2 pixels. Pretty neat!