Global Mobile: Connecting without Walls, Wires or Borders (Peachpit, 2005) by Fred Johnson is a small and basic guide to getting around with a laptop, cell phone or handheld device.
It is a handy guide for the uninitiated who want to take a laptop out of the home or office to an internet hotspot, want to travel abroad and use a cell phone, want to use text messaging from a phone, want to work on the road, or want to use Bluetooth.
It includes a few beyond-the-basics tips like how to create a wireless computer-to-computer network and how to connect a laptop to a cell phone for internet access using a cell phone. The appendices include GSM frequencies (for cell phone use abroad) by country, and telephone country codes.
This book can help you sort out what the technologies are and what equipment you need to get started with them.