OpenGL texturing

[Francesco Orsenigo <xarvh@lombardiacom.it>]

How can i load a texture to use within OpenGL calls?
Each demo/tutorial i see uses different functions, many of wich are not 
native OpenGL...

I'd need to perform many pixel-by-pixel color transformations: is this 
possible after the texture is loaded?

Example:
    for(each pixel)
          if(pixel->red != 0 || pixel->blue != 0)
	draw pixel;   //draw the original pixel as is
          else 
                   draw table[pixel->green];   //use the green value to draw 
a different color




Thanx to all,
Francesco Orsenigo