Furniture Refinishing Advice

So - all of you Payne men who know about furniture, tools and fixing stuff -
My dining room table's finish is gone. The clear stuff on top that protects from markers, crayons and stains is gone. The top is not shiny anymore, it's flat. So I need to put some clear polyurathane (sp?) or something on it.

How do I go about doing this? So I need to sand it?
Can I change the color of the table? I'd like it to be darker.

I've already thought about just covering it with a vinyl table cloth because that would be easiest.
I've already thought about begging dad to come help me, but he's going to be too busy to come down here.

So what should I do with it?