Yes, it's built in and works similarly to the wifi on the iPod Touch.
the first has wifi and the second does not.
That means the Wifi adapter is built into the console or computer
They mean the same that if you have a WiFi connection the devices are ready to b receive the signal
Built in means that it is comes with wifi ability right out of the box. So, you will get built in wifi if you buy a laptop that has wifi built in. In the specifications, look for WiFi, WLAN or for...
yes, there is another 3g version as well.
Advanced WiFi Troubleshooting Tips
Basic WiFi Troubleshooting Tips
How to Use WiFi with iPhone
Barnes and Noble Add a WiFi-Only Nook CNET Loaded 06/21/2010