We are paying for their undergraduate degrees; haven't decided yet about what/if we will contribute for any graduate schooling.
My mom and grandma died when the kids were young, and we were fortunate enough to put aside $$ for college funds for both DD and DS. We hope that it will cover tuition, room/board and books, but you never know. When we got our first tuition bill in August, I was stunned at all of the fees assessed for this or that. Man, they nickel and dime you to death!!
DD is a freshman at one of our state universities. She is responsible for "fun" money, i.e., pizza, ski pass, clothing that she wants over and above the annual amount we give her to buy replacement stuff, etc. I put $160 in her checking account each month as an "allowance" to help cover the cost of laundry, groceries, shampoo, etc. So far it's worked out well. I made her write out the tuition check, so she could actually SEE how much her education costs. Nothing can sober an 18-year-old up quicker than writing a $7,000+ check!! She doesn't have a job, as we thought it was too much for her first semester. But she's talking about getting a part-time one on campus next semester, so we'll see if that happens.
DS will likely go to the same state university, so I would imagine his financial arrangement will be the same.
We want them to graduate debt-free from undergrad, and then use as many of their own resources as possible to pay for graduate school, if they choose to attend one. I think they value it more that way, although if they get in a financial bind, I'm sure that DH and I will help if we can.