What you need to do is set the Normal property of the Text. Depending on your need, figuring what normal vector to use could be a little tricky.
The normal should be a unit vector (a vector whose length is 1). For common 2d or 3d objects placed parallel to the XY plane, the normal is (0,0,1). If you wanted to place text parallel to the XZ plane, for instance, you would make it's normal (0,-1,0)
Dave O.