The Short Answer: The amount of money the government has printed has not yet exceeded the money that was created by banks during periods of record low interest rates.
In other words, when you deposit money into a bank, they are allowed to keep only a fraction of that on reserve. They can lend far more money out than the amount you deposit. Here's a gross oversimplification: If reserve requirements are low (set by the Federal Reserve), and you deposit $100,000 into your bank, the bank may only need to keep $10,000 on hand. They can then lend $90,000 out to someone, who goes and deposits it another bank. This bank can then use the money to lend out $89,000. This cycle repeats until your original $100,000 is much, much more "money" in the system. In our case alone, your deposit plus two business loans resulted in $279,000!
The government, economists, and financiers track the amount of money in the system by the type. These are often called M1, M2, or M3 money supplies. They way, they can see how much of the "money" in a nation comes from paper dollars, how much comes from bank credit, etc.
So much "money" was created when interest rates fell and consumers borrowed record amounts that when the banks shut off the lending to try and rebuild their balance sheet, that money was sucked out of the economy. Had the Federal Reserve not printed money, we would have gone into a Great Depression deflation - your house and assets would have lost value but your mortgage would have stayed the same. In other words, if you had any debt at all, you would have been totally and completely screwed.
The government turned on the printing presses to attempt to replace the bank created money, with the hope that they could take it out of the system over the next 5 to 10 years slowly, a little at a time.
This was a perfectly rational and wise response. The problem is that many people wonder whether or not Congress can control its spending. The moment the printed money starts to exceed our old money supply (printed money + bank created money), inflation begins. With the current projected deficit of $9+ trillion over the coming 10 years, that would happen and that is why people said inflation may be coming.
If Congress stops spending 1-2 years from now, inflation won't happen despite the money we've printed because of the factors I've already described. If, however, Congress continues to spend money, inflation could destroy the value of the dollar. As I've posted earlier and elsewhere, if you know how to take advantage of this situation, that can be good for you, just as it will be for companies such as Coca-Cola, General Electric, or Johnson & Johnson, which make a lot of their money overseas in non-dollar countries.
Put simply, the problem isn't the money the government has printed over the past two years. It's the money that most investors think the government is going to print over the coming ten years that is the problem. As you can see from the chart below, actual paper money is a tiny, tiny percentage of the total "money" a nation has created at any given time. As a result of credit getting cut off, the government couldn't print money fast enough to replace the M2 and M3 money supplies (this chart shows you up until 2005, how M2 and M3 were getting to be a larger and larger percentage of the total "money").