Is Blackjack beatable?

[ianlippert]

The other day I was having this conversation with my friend. I've always heard that it wasnt, he seemed to think that implementing a simple strategy could make you a winner. I argued that if it was simple everyone could make money off the casino. He isnt really knowledgable in areas of statistics, so I figure I'm right.

But why exactly is blackjack not beatable? Where is the casinos edge? What exactly is card counting, and how can it make you a winner?