Does anyone know if these use "normal" Office setup disks, or the limited-use MDSN/Technet ones (usually brown in loose sleeves)? The two types use different product key sequences
If they are normal ones then you can legally download the ISOs from Digital River, and use them with your product key. If they are MSDN/Technet ones then I don't think theres an official M$ download link, though you can find them on The Pirate Bay (usual warnings apply)