"Is the Palm software that powered the first practical handheld in 1996 and redefined mobile computing on the road to oblivion? It sure looks that way, at least for devices such as Palm's popular Treo, which combines voice and e-mail service with the traditional contacts and calendar functions of a personal digital assistant. Palm will soon announce a Treo powered not by Palm OS software but by Microsoft's Windows Mobile 5. And while Palm will sell both Palm OS and Windows Treos for the indefinite future, Microsoft software is likely to dominate the market over time."
There is some interesting background information here too on Palm's bid for PalmSource that eventually wound up at Access a week or so ago.