I was informed that it may be advisable to take a long term gain on a
Stock in my portfolio to pay college tuition resulting in (for my tax
bracket 10%)a 50% reduction of tax liability. 5% is a great deal!

I just have to provide proof to IRS that the proceeds were used to pay
tuition. I tried to look around www.irs.gov for the requirements, but
can't find anything on the rule.

Who gave you this advice? The broker? This is nuts. If you hold the stock long term and sell it, and your profit doesn't bump you into the 25% tax bracket, your long term capital gains will be taxed at 5%. It doesn't matter who gets the proceeds or even if you turn around and buy the stock back.

Scottrade said all they would need from us is a note from me and my
wife authorizing them to issue a check to the college. For proof,
would a copy of the Sale Confirmation and a copy of Scottrade's monthly
statement be sufficent to satisfy IRS?

There's nothing to satisfy, because there is no such tax benefit. The money you pay to the college may provide a tax benefit to you. You will have to work out whether you qualify for a Hope credit or a Lifetime Learning Credit or whether the straight tuition deduction provides a greater benefit. Again, there is no advantage to taking the money from a stock sale.

I have saved cash on the side to pay for my son's tuition. I
don't really want to sell the stock, but if I buy it back with the
ready cash on the side, I would be starting with a new base.
It certainly sounds like a smart idea.

Sure, it's a smart idea if you're the broker and get two commissions out of it. (I realize Scottrade has low commissions so they're not making much.) Not such a great idea for you UNLESS you know you will be moving up to the 25% tax bracket in the future and will be facing 15% long-term capital gains rates instead of 5%. Sale and repurchase not only resets the cost basis, it also resets the holding period. If you find yourself selling within a year of this transaction, any gains will be short term, not long term.

My son will be attending in the fall. I am trying to plan for
this strategy in advance.

Forget this strategy. It doesn't make sense.

Ira