can't include gl.h and glu.h [SOLVED]

[Gmaj7]

I tried this tutorial http://www.sfml-dev.org/tutorials/1.5/window-window.php
and got following error.. what should I do?
I'm using Ubuntu 9.10 , Codeblocks

It seems to me that can't find opengl?

/home/laman/Cpp/SFML-1.5/include/SFML/Window/OpenGL.hpp|47|error: GL/gl.h: No such file or directory|
/home/laman/Cpp/SFML-1.5/include/SFML/Window/OpenGL.hpp|48|error: GL/glu.h: No such file or directory|

||=== Build finished: 2 errors, 0 warnings ===|

[Laurent]

You must install the GL and GLU packages.