How can I render a cubemap with Blender Internal? I need to render a cubemap from a Blender scene.

Is this the correct way to do it?:

Set camera FOV to 90.
Have one camera facing up, one down, left, right, front , back.
Is that all to achieve a proper seamless cubemap?

If not, how then?
Regardless of which render engine you use, the process is the same.

It has been explained well here.

Personally I find rendering a single-image equirectangular environment map to be easier, but I understand you may have specific reasons for needing a cube map.