Thanks for the info! I have an IRA with Scottrade but hadn't heard about this program yet. I will think about it for a little while, and will probably sign up. Being able to re-invest dividends for free is better than paying a commission, even if the trade is done at a pre-determined time.
I don't think I would do this for a taxable account, just because having so many small share lots makes computing capital gains tax more of a pain.