In the last post I made mention of the fact that I hadn't heard anything from SMARTHOME regarding my order which included in the USB version of the Insteon SDK.
Well I called SMARTHOME yesterday and they told me that they would be unable to fulfill that order because the USB version was not longer producted, so I cancelled the order. Today I called them again and learned that their Serial SDK was still available, though it was listed on the site as backorder.