According to the federal law, the most you can save in a 529 account is the expected cost of higher education—so states have set some limits based on that guideline. On an annual basis, any amounts over the annual federal gift-tax exclusion would need to be reported to the IRS as a gift and would count against your lifetime gift tax exclusion. You can "superfund" a 529 by contributing 5 years' worth of your annual federal gift tax exclusion.
To learn more about the gift tax, read Viewpoints: What to know about giving money