Touch screen is not the technology being demonstrated by Microsoft or that is already being shipped by Apple. It is Multi-touch, the ability of the screen to sense and react to multiple contacts at the same time. Apple holds the patent on that.
They should sue Microsoft then, and put Google on notice their new Android phone can't have those features either. At least that's my understanding of what patents are for, unless there's a cross-patent license or other agreement that's more important. Companies and groups that innovate should be protected and nurtured, while those that duplicate protected technologies should have to wait a lawful time or face penalty.