New to shorthand - which one should I try?

I'm a writer and I usually do all of my manuscripts on the computer.  I type over 90 wpm so I'm fine as long as I'm in front of a computer, but I now have a 90 minute commute (1 way) to work and I'm finding that this is when my best brainstorming has been coming into play.  The problem is, I can't exactly whip out the old laptop, and by the time I try to get it down in long hand, I've either lost the thread or it's stilted at best.  My brain thinks faster than my hand works, so I'm losing my best work before I ever get to my destination.  And after working 8 -9 hours a day and commuting for 3 (not to mention kids, dinner, homework and the like) I don't have a lot of time to spend on personal writing at the end of the day.
Which method is the easiest to learn in the shortest amount of time?  My mother is an old Gregg user and I've tried to learn from her but didn't spend enough time on it to get any real value, not to mention I was too young to appreciate the skill at the time.  I have 4 manuscripts I'm actively working on and my goal is to get at least two submitted by end of 2006, so I need something that won't take a lifetime to learn.
I'm a blank slate here totally open to suggestions!
Thank you!

(by mtggirl for everyone)