I am currently developing a 3d game for Win32 using OpenGL (however, I still use Direct3D retained mode for 3d-transformations). I’ve not found function either in OpenGL or in WGL to setup video mode and fullscreen rendering. When I use software driver (GDI generic), I can use DirectDraw in exclusive mode to setup video mode (I am not creating even primary surface, just setting video mode and then rendering through GDI). When I use standalone OpenGL driver for my video card (Voodoo Rush based, I copy 3dfxvgl.dll to opengl32.dll in my game folder), this driver sets video mode for me (it supports only fullscreen rendering) based on initial window size. When my friend tested game on his i740, the game won’t run in fullscreen (OpenGL init after ddraw init failed), but if game not try to use DirectDraw, it runs in windowed mode.
I guess, there must be correct way to setup video mode for Win32 OpenGL program, but for now I haven’t found one 
So if you know something, email me (or post reply)
I think you want to do this:
ChangeDisplayMode(&display_settings, CDS_FULLSCREEN);