It seems that this question pops up every month or so. Welcome to the boards
It's very difficult to use one of these units as a monitor/amp combo - they don't expose a standard video interface, like VGA or DVI. Not to say that it's impossible - you can probably figure it out eventually. The interface they use is most likely LVDS - similar to what laptops use when they connect to monitors. The touch screen interface also needs to be hacked .
If you want to just replace the software/OS, you will realize that most of these units are way underpowered to run a decent frontend. If you plan to install a different OS, like Ubuntu or Android, you'll have a hell of a time trying to find the drivers that will work.
All in all, I'd say that these units are more trouble than they are worth.