:( If I use a black texture with one red texel on it(so I can easily identify it), and texture a triangle on a polygon in 3D space - I notice that that texel does not appear at the same location if I manually transform the texel by pretending it's a vertex and using D3DXVec3Project. (Although it appears to work on regular vertices). The triangle is exactly the same dimensions on the texture map so I thought it would work. Maybe it has something to do with the way the texture is interpolated accross the polygon? They appear close but several pixels off most of the time. It's weird. Any ideas on how I can get the true screen position of any given texel? Any suggestions or comments are completely welcome. :)

My guess would be that the problem is with your calculation of the texel's position in 3D space. I can't tell you how to calculate that, but if you post how you determine that, I may be able to find the problem there.