Here's what I remember from my civics class.
Before the Civil War, taxes were collected by the gov't through tariffs and on taxes on things like gold, silver and alcohol. During the Civil War, however, the nation's debt was too large to be covered by the old system of collecting money and an income tax was instituted to bring the books back square.
I know there were several different income taxes proposed, but income taxes were ruled unconstitutional by the Supreme Court in the 1890's (94-95?) I've read that it was because the income tax wasn't apportioned to the states as the Constitution requires, but the 16th amendment clearly states that it doesn't need to. Maybe I'm not reading that right, or clearly understanding it.
When the income tax amendment was ratified in 1913, the Federal Reserve was set up and income tax became mandatory.
I'm pretty sure that the I.R.S. is a goverment agency and not directly connected to the Fed, which isn't under the auspices of the federal goverment. That's why, even though Greenspan had to get Congressional approval to serve, he is under no obligation to "answer" to them.
This isn't the first and only Federal Bank. There were two other 'National Banks' in the early part of our history, that were run by some unscrupulous fellows. The charter on the second National Bank ran out during Andrew Jackson's term. Jackson's opinion of the bank wasn't high to begin with. He seen it as rich white folks' holding rich white folks' money and helping rich white folks' with their troubles.
I've read that 3/4 of the states are needed to ratify an amendment to the Constitution. The argument I've seen a lot of says that there wasn't enough to ratify it so the gov't "ratified" it anyway through Congress, which I'm pretty sure they aren't allowed to do, which makes the 16th amendment unconstitutional. So somewhere there are states that haven't ratified the 16th amendment for income taxes, but they make us pay anyway.
I can't find anything that isn't blatantly Anti-tax or Pro-tax. The closest I've come is this website
http://www.unclefed.com/Audit-Proofing/step4-2b.html
It lists court cases that you can research to verify if ol' Uncle Fed is reporting correctly.