Swine Flu? Or Virus?

What is all this about the Swine Flu?

What is it? What happens to you if you catch it?
Does it kill people? I know that several people have
died, but it seems to have only killed people who
are weak.

It's contagious, and there are roughly 30 cases in
the US right now. And I know that there are plenty
of cases in Mexico.

Is this gonna be another pandemic?