iHub has either a 1-week or a 2-week free trial for their L2 service. I believe you can try it free for a week without giving them a credit card up front or free for 2 weeks if you give them a credit card up front.
And yes, they have a nice tutorial on it. Click on the Level 2 link up at the top of any iHub page, then scroll down to the bottom right-hand corner, and there is a link for "Level 2 Video Tutorial".
There might be some other good L2 services out there. I just chose to use iHub's since I'm here fairly regularly.
I know it is not directed to me but yes it shows who is on the bid and ask. Gives you a better perspective on whether the stock is moving up or down. You don't want to sell a stock when L2 is showing an upward trend and vice versa...It is good to know if more people are willing to buy on the bid than sell on the ask..