querying memory on boards

Is it possible to query the total memory available and the current free memory on-board on either the GeForce or Radeon cards?

I know I can know what total memory is available if I put the card in, but if I want develop software for third parties, or non-specific machines, then I need to know the total available memory.

thanks

This is not at all possible in OpenGL. You are supposed to design your software to work without knowing much about what HW you are running on.
DX can do it… but you can get used to work without this feature.
For textures, maybe you should look up textureproxies, they let you know if they are currently placed in highspeed area.