You can use NinjaTrader (even the free Simulation Edition) with TradeStation's real-time data feed.

Initial Set Up

1. NinjaTrader must be installed

2. Start TradeStation

3. Select the menu File-->Import/Export EasyLanguage

4. Select "Import EasyLanguage file (ELD, ELS or ELA)"

5. Click "Next"

6. Select the file <NinjaTrader Installation Folder>\bin\AutoTrade\NINJATRADER.ELD"

7. Click "Next"

8. Click "Next"

9. Click "Finish" and confirm any upcoming query box by clicking "OK"

Connecting

1. Start NinjaTrader and connect to the "External Data Feed Connection" via the Control Center window, File-->Connect menu

2. Start TradeStation

3. Within TradeSation, open a chart window (@ES for example) and via the right mouse click context menu, select "Insert Strategy..."

4. From the dialog window "Insert Strategies" select "NTExternalFeed" strategy and press the "OK" button

5. A new window will appear "Format Analysis Techniques & Strategies", press the "CLOSE" button

6. Within NinjaTrader, select the current ES contract from the instrument list (ES 03-07 for the March 2007 contract as an example) from any of the order entry or chart window

You will now receive real-time data from TradeStation in NinjaTrader.

* Only level one data will be transmitted. Market depth is not supported.