Also there are some weird gift tax rules for 529 plans (from same Merrill site):
Withdrawals for qualified higher education expenses are tax free.
There are no income restrictions on the ability to contribute and typically no annual contribution limits, although annual contributions of more than $14,000 ($28,000 when made jointly with a spouse) may require filing a federal gift tax return (and in certain cases, could cause you to be subject to federal gift tax). You may contribute five years' worth of gifts all at once, or $70,000 per beneficiary, without triggering the federal gift tax.
Merrill gives you $50 to open a 529 plan, but its administered by the State of Maine (?!)