First of all, if you claim him as a dependent on your return, he won't be eligible for Pell Grants, and likely won't qualify for much in subsidized loan money. Pell grants are worth up to something like $4000 per academic year, and do not need to be repaid.
Also, your expected financial contribution (EFC), calculated by FAFSA, may be substantially higher than you'd expect. Mine was around 20% of my annual income, and that was for a fairly low cost school. That's a big nut for most to shell out of pocket or finance at ~8%* with unsubsidized loans. This means YOU will likely have loan payments throughout and beyond your son's college days.
Another way to approach this is by NOT claiming your son as a dependent. This will of course lower your tax exemption, but it will also enable son to claim Pell Grants and subsidized loans. These loans don't go into repayment until graduation, and the interest until school completed is picked up by the gov't.
Best advice is do the math for both approaches and weigh the two options.
*Anybody remember the good old days when almost all college loans were subsidized at 2%?
