The Handspring Treo 300 was the first elegant pairing of Palm PDA and cell phone. Its eagerly awaited follow-up, the Treo 600, keeps up the family name with a built-in camera, a memory-card slot and a much brighter screen. Inside, amenities include an updated Palm OS, 32-MB of onboard memory and a processor four times as fast as the Treo 300's. Of course, you'll still have to contend with the cramped little keyboard. Expect the phone to sell for around $550 in mid-October; Sprint PCS will be the first to offer service. GSM versions offered by Cingular and T-Mobile are expected to follow. --W.R.