[font=Arial, Helvetica,]i know how to implement the A* algorithm.but how do i use it in my engine?
if i get a polyline, how am i gonna able to drive on it.

In addition to this, the rules governing whether it is
possible to navigate from any given point A to a secondary
point B are entirely dependent on the skater’s state
at point A. The state required at point A involves a large
number of variables, as well as a complex set of previously
executed maneuvers to have reached it.

lemme put it with example

my car is on postion (0,0,0)
i wanna go to (10,0,50) then to (20,0,70) and so on,
i have methods for accelerating,bracking,steering left,right.
if the point is straight ahead, i want to accelerate, if it is not, i have to steer.
its simple enough to say, but i m not able to implement it.
how am i gonna able to solve this problem. if not code then an algorithm explanation with example will be very nice. thanku[/font]

seems like this what you are looking for: http://www.gamasutra.com/view/feature/3096/toward_more_realistic_pathfinding.php?print=1 .I never used it so i can't really help.