Congratulations on becoming grandparents!
You definitely want to open an Illinois BrightStart 529 plan account.
Go to www.BrightStart.com. Your contributions are tax deductible on your Illinois income taxes — up to $10,000 per year.
When asked how you want to invest, just use the “age-based” plan, where the investments get more conservative the closer they get to needing the money for college.