How can I help my son become more independent before he leaves for college?
Parenting is a balancing act; we try not to do too much or too little. Developing independence is an ongoing process throughout a child's life. And for kids who are getting ready to go away to college, they must develop a sense of independence and self-reliance. Give him as much freedom as you believe he can handle. But my motto is: Abuse it and lose it. He should be taught to take care of his own needs, such as laundry and shopping for incidentals. He should be handling his own money: Open up a checking account and even have him apply for a student credit card (with a small limit) for emergency purposes and so that he can establish his own credit.
Teach him the evils of debit cards. Kids tend to forget to record these transactions and are then surprised when they are overdrawn. Also, because he needs to demonstrate good judgment and decision making, give him plenty of latitude to handle situations on his own. It's difficult to sit back and watch our kids make mistakes or poor decisions. However, at least he can do this while he's still home so that you help him through it.
You can't shelter him. You want to feel that when you send him off, he has the tools and skills to make it on his own. As long as he lives under your roof, you have the right and responsibility to set parameters like curfews. The important thing is to make sure that these parameters are not too restrictive, giving him enough space to demonstrate his maturity and readiness to move away.