Sorry kids, time to pony up.
The first thing parents have to do is think about their own retirement.
There are ways for your children to finance college: scholarships, work-study programs, subsidized federal loans, unsubsidized federal loans, Sallie Mae loans, CitiBank "CitiAssist" loans (for part-time and non-traditional students), etc.
If parents have their retirement fund perfectly set up and well-planned from a very early stage, they can then think about setting money aside (perhaps in a Roth IRA) that can later be put toward college tuition.
It is of the utmost importance for parents to realize that they should not bankrupt themselves or endanger their retirement funds by footing the bill for their kids' college education. There are other ways of helping your kids, and there are plenty of programs geared toward helping your kids finance college, but don't touch that retirement fund!