Reply to Joystick and POV (point of view)

I'm just wondering, how does the POV work on joysticks?

I'm about to start some mods. Considered an old Trust JGM2550 joystick I have as the brain. It's USB and plug and play, so no drivers needed for Windows. Here it is:

http://www.trust.com/products/product.aspx?artnr=15077

I'm wondering, how does the top POV 8-way button work? Also, there's things like a throttle lever (assumingly analogue) and there's the joustick movement as well as the fact it twists from side to side.

I'm just wondering if it's possible to incorporate this as a brain with plenty of buttons and a few analogues. I'm just wondering, if it'd be possible to hook up something like a DS screen to it to make a Kaoss Pad type X-Y control using the POV connectors?

I know nothing about this stuff, but just prodding ideas at the moment!