Parabolic Movement

I was always hopeless at maths… I wasn’t actually too good at archery either. So I’m having trouble coding the flight of an arrow through the air. I want something very much like this game…

http://www.miniclip.com/games/loves-arrow/en/

I have the bow working, an arrow does fly from it when the string is released. I have also managed to get a value for the power of the shot from the distance the string is pulled back to. The main problem is the physics behind the flight.

Has anyone had previous experience of this or something similar? I’d really really appreciate any advice or help

Cheers all