I've heard Jessica Alba has been confirmed to play Sue Storm. Which I really have a hard time seeing, given how.... white Susan Storm is usually portrayed in the comics.
As for Victor Van Damme -- I've heard the flick will be based more on Ultimate Fantastic Four, not the mainstream Fantastic Four comic. In that, Victor Van Damme (who can trace his lineage back to Count Vlad Tepes Dracula) was in the same think-tank as Reed Richards & Sue Storm (in the UFF, Sue's a highly intelligent biophysicist, and is actually a few years older than Reed), and all 5 of them (Van Damme + the "Fab Four") were caught in the Quantum Inferno that gave the FF their fantastic powers. Van Damme's skin changed into something resembling riveted iron plate armor (with little-to-no pain receptors), and his legs were changed into backward-bending goat/demon legs. And, of course, he blames Richars for the accident, even though it was he himself who tampered with the teleportal device to 'correct' a 'flaw' in it that he was sure Richards had overlooked.