Object rotation...

Thanks to dustwolf, i managed to get the nehe tutorial 10 modified to a point where the world moves in a sphere around me, but i still havn't gotten the rotation of the objects down, yet. I'm working with C++ code right now and converting it to assembly, later, so i can get input from non-asm programmers as well.

Code:

    //The following 3 lines is for the location... No problem here...
   xpos += (float)sin(xheading*piover180) * 0.005f * SPEED; 
   ypos += (float)sin(yheading*piover180) * 0.005f * SPEED;
    zpos += (float)(cos(xheading*piover180)*cos(yheading*piover180)) * 0.005f * SPEED;

      //This is where the problem is. The ifs were an attempt to fix
      //the issue with flipping upside-down and the left and right
        //movement get reversed. Worse yet, if you look up and turn
 //it's like you're spinning the z, not the y like i want.
 //So, my guess is that here is a good place to start.
       glRotatef(yheading,1,0,0);
  if (yheading>90 || yheading<-90)
              glRotatef(xheading,0,1,0);
  else
                glRotatef(-xheading,0,1,0);
 if (yheading>180)
                yheading-=360;
      else if (yheading<-180)
          yheading+=360;
      
    //Would look prettier near the location calculations, but
   //for some reson the effects are a bit awkward if i put
     //this before the rotation situation.
       glTranslatef(xpos, ypos, zpos);

Worse yet, after i solve this i'm going to need to change the controls yet again, for i'm looking for some what of a "jet flight effect." The idea is, after fixing this, it might give me some idea on how to set up a system where i turn the world around me then go up or down to go right or left or diagonal, like your traditional flight simulator, but first i'll have to get an idea on how to get this out of neutral. Any ideas at this point would be appriciated.