Let's start by admitting that PDA/phone combination devices just can't be as small and light as regular cell phones. Crucial PDA considerations, such as display visibility and input convenience, work against size and weight. But if you don't insist on a tiny form factor, you'll find highly functional and reasonably mobile multipurpose devices. The new Microsoft Windows Powered PCS Phone SH-G1000 by Hitachi ($650 street), with service provided by Sprint PCS, is the current category leader.