Yes, if you transform the unit cube by (Mview*Mprojection)-1,you'll get the frustum corners in world space. (for row major matrices, (Mprojection*Mview)-1 otherwise)
EDIT : when I said row major matrices, I meant row vectors with matrix pre-multiplication
So, (Mview*Mprojection)-1 in DirectX.
And, AFAIK, (Mprojection*Mview)-1 in OpenGL