Currently I am using eTrade Pro, but you can get a similar one from TD Ameritrade (I used to use this account just for the L2). I am using an apple which allows for an actual screen capture (rather than a print screen) so I can take a snapshot of any portion of the screen.
Cat, you can sign up and download TDA's Think or Swim platform without opening a real account. They have a 'paper trading' option, which still has access to the platform and Level 2 (as far as I know).