Future VS Spot movement

Hi,
I am a beginner and want to understand how the future prices are moved against spot prices for an equty? Are these 2 independent of each other?
Also if there is a contract today 16/04/2009 ending on say 30/05/2009 for an stock A at 1500/share, does price for this contract change as the time pass? and is this change is what the profit/loss for me?

also where can I find a chart for above mentioned movement in price of contract w.r.t time?

Thanks in advance

Parul

Here you are.

http://en.wikipedia.org/wiki/Futures_contract#Pricing

Thank you for the link.

I read following in the link that you provided. Would you be able to explain this with example?

" Futures, on the other hand, are margined daily, every day to the daily spot price of a forward with the same agreed-upon delivery price and underlying asset"

Thanks