As there is no free lunch in this world, it would mean that the Palm Pre/Pixi which runs on webOS 1.x will be unable to make use of key TouchPad features such as Touch-to-Share or messaging integration. Shared calling might work though, with the HP TouchPad doubling up as what some might dub to be one of the largest Bluetooth headsets you have come across.
Will HP expand the program to encompass newer handsets? We sure hope so, considering how archaic the Pre and Pixi device are already. You will need to retain the serial number of your smartphone as proof of purchase in order to qualify, no receipts required. The receipt for the 32GB TouchPad and the UPC code are required though, but make sure it is used with any purchase or pre-order as long as you send it in before July 31st.