Dunno about that as there are few reasons to include such functionality. But there are a few handheld computers that include a cell phone.

More common is a USB or serial cable that plugs into the phone and into your computer. With software that either comes with the cable or is downloadable, you can copy your addrerss book to the computer and edit it there. Some extra cost software will do things like let you update appointments on the phone.

And, of course, the cables let you use the phone as a modem.