If I take a cash disbursement from my IRA, and give that money to my son to buy a house, do I still pay the full income tax on that money?
Yes. The tax applies reguardless of what you do with the money.
If you are under age 59 1/2 then there could be an additional 10% early distribution penalty that might be waived for the first $10,000 if the money is used to purchase a first home and all of the other conditions are met.
This assumes you are asking about a Traditional IRA and not a Roth. For a Roth, you can always withdrew your own prion contribution tax and penalty free. The tax and penalty applies to any earnings that are withdrawn.
Money that you receive as a gift is not taxable income to you, and you do not need to report it on your income tax return. Money that you gave as a gift to someone else is not deductible for your taxes.
Turbo Tax does not support the gift tax form 709, but here is a link: