Hi Allen, Re: Extended Hours Trading...................
I think most on-line brokerages have this feature today. However, you may have to look around in your Order Entry page to find all the various options. The usual suspects are Market and Limit orders, Day orders and Good 'til Cancelled (GTC) orders.
After that you can find, sometimes in a drop down menu, "Extended Hours" trade qualifiers and other things.
I know Ameritrade has this and I believe Schwab does too. I would guess that Scott and many of the others offer these as well. Some of the deeper discounters used to add a small extra charge for such trades, but I don't know if that's still true.