dual monitor support

With setting up dual monitor support, do both monitors have to be connected by the same interface.
Explanation:
My video card is an upper end card with 256 megs of DDR. It has two ports. One is VGA,and the other is DVI-D.
Is it possible to take two monitors, exactly alike, both with dual input connectors (one VGA, the other DVI) and use them as dual monitors by connecting one to the VGA and the other to the DVI of my card?
Or, must they both be either VGA or DVI?