Code:
Public Sub MatrixMatrixBillboardTranspose(result As D3DMATRIX8, a As D3DMATRIX8 , x As Single, y As Single, z As Single)
	result._11 = a._11
	result._12 = a._21
	result._13 = a._31
	result._14 = 0.0

	result._21 = a._12
	result._22 = a._22
	result._23 = a._32
	result._24 = 0.0

	result._31 = a._13
	result._32 = a._23
	result._33 = a._33
	result._34 = 0.0

	result._41 = x
	result._42 = y
	result._43 = z
	result._44 = a._44
End Sub
Pass in a matrix that will retrieve the result of the function. The second parameter is the current view matrix. The three Singles are the position of the billboard's center. The fucntion will then compute an appropriate billboard matrix. You then multiply the resulting matrix by the vertices that make up the billboard itself. It should align the billboard to the camera.

Z.