Ah...in short it's something that can transmit sound through various electrical means. The PokeGear can also show video, which is...well, basically a moving picture of whatever the machine's 'eye' is pointed at. It makes keeping in contact when you're out traveling a lot easier.

Mmm, you're not anywhere near where you were before. We all get dragged here by something, we haven't figured out what. This place is called Johto, and the town you're in is called New Bark.