2d - How can I make a sprite move in the direction it's facing using radians?

I am using PGELua for the PlaystationPortable. I would just like to know how to make a 2D sprite move in the direction that the sprite is facing.

When the sprite is blitted to the screen it should be heading down the y axis (like it's moving up the screen) but it doesn't appear to be working that way. As far as I am aware, the angles of the images use radians for the rotations.

I have this in a function

function FUNC_MOVE_SHIP(speed,angles)
    VAR_SHIPX = VAR_SHIPX + pge.math.sin(angles) * speed
    VAR_SHIPY = VAR_SHIPY + pge.math.cos(angles) * speed
end

and I call it in my main program like

    FUNC_ST_DR()
    if pge.controls.held(PGE_CTRL_LEFT) then
        VAR_SHIP_ANGLE=VAR_SHIP_ANGLE-0.01
    elseif pge.controls.held(PGE_CTRL_RIGHT) then
        VAR_SHIP_ANGLE=VAR_SHIP_ANGLE+0.01
    end
    FUNC_MOVE_SHIP(VAR_SHIP_SPEED,pge.math.rad(VAR_SHIP_ANGLE))
    SHIP_11:activate()

    SHIP_11:draweasy(VAR_SHIPX,VAR_SHIPY,pge.math.rad(VAR_SHIP_ANGLE))
    FUNC_EN_DR()

Answer

A common problem with using radians is that they start to the right. Look at this picture (from Wikipedia):

As you can see, it starts at 0 on the right of the circle and goes counter-clockwise around the circle until it hits 2 * PI. So if your sprite isn't pointing to the right with a rotation of 0, you might have to add some constant. Eg. if your sprite is pointing up, you have to add PI * 0.5 to the calculated angle. Also, instead of adding and subtracting 0.01 from the angle, I'd rather choose some fraction of PI instead. Eg. PI / 90 equals 2 degrees of rotation per update.