I'm not really up on any of this SAD stuff, so I don't know if what I have applies, but I have an alarm clock that has a light bulb attached to it. I set the alarm for 5:30 am and at about 5:15am, the light starts to come on, simulating a sunrise. By the time 5:30 hits, my room is bright and it's pretty easy for me to get up.
You can set it to start coming on 15, 30, 45 or 60 minutes prioir to your alarm. You can also do the same when you are going to sleep. You can read a book and get it to dim until it is off simulating a sunset.
I've had mine for 10 years and really beats waking up in the pitch black in the cold.
It's called a biobrite sunrise clock and looks like this:
