It will just run at 100Mhz FSB and down clock the CPU's speed accordingly ( ~100Mhz depending on what the multiplier is set at).
But to be honest you could just pick up a nicer board with the CPU for extremely cheaply and not worry about the FSB limitations. How much does it cost to send stuff to the US? I could send you a
DFI LanParty Socket A board for free if you'd pay P&P.