Yes, the graphics card memory (actually GDDR3, different than DDR3) has nothing to do with the system memory (DDR2) so as long as the board has a PCI-E (x16) slot, you should be all set.
What is the specification of your PCI-e of your mainboard? If it is at least vesion 1.1 then 8600GT will wotk fine on your mainboard. But there is a compatibily issue between version 1.0 with 2.0. So there might be issue running a PCI-e V2.0 card on a V1.0 slot.
i don kno about d version of dat PCI-E ......motherboard is intel D102glcc...wud u plz let me kno abt d version..and whether it is a rite choice to buy 8600gt ddr3 for ma motherboard???..thnx