Nothing has been said officially, but between the lines Tim Cook said at the Apple Earnings Call that Apple would go after any company ripping their IP off. He did not mention Palm, but the Palm Pre is the closest multi-touch smartphone competitor now to the iPhone.
Palm said that they are confident to be able to defend themselves in potential legal battles. Statement Via AllThingsD.

Palm is not a new company to the portable world and has been selling smartphones longer than Apple. Palm had many good years and they have created a strong patent portfolio that will be offering quite a bit of protection.
Anyway the battle is on between the Apple iPhone and the Palm Pre even before the Pre has launched on Sprint.