Are there any websites that tell you how to beat the computerized blackjack machines at the casinos?

Sure. There are also many books on the subject. You can't beat the machine by any method no matter what they tell you. I own an electronic slot machine and play it often in my home. I have the keys and can change the odds on the machine so it pays more often or less. There is no way to beat a casino machine so save your money. The only way to know about pay out is to have a friend who works the machines as a change girl. They know which machines pay better than others.