Red phone icon extreme upper left corner of screen?

I've recently been given a Samsung GT-S5360 Y for Christmas. This is a new world for me, so please be tolerant if my questions seem a bit dumb.
First of all, I notice a little red phone receiver with a bent white arrow, seeming to bounce off it. What does this mean? How can I take it off or keep it?
Also, what is a 2G Network?
I really have tried to find the answers to these questions in the Samsung online manual. Is there another online manual that deals with more basic problems for us Android Dummies?

Thanks for your help,
Ron (as you can see, I'm enjoying the emoticons!)