TradeKing is an investment brokerage - for more details please visit their website at www.tradeking.com
In order to use TradeKing as a source of streaming live (or delayed) market data you will need to have a TradeKing trading account.
After selecting TradeKing in the Data Feed Section (see here) as your data source you will be presented with the following login screen:
Enter your TradeKing Id and password and press "Login" - you will then be asked to allow account access to OptionNET Explorer:
Press "Authorize!" and you will now have access to TradeKing streaming market data.
Please note that you will only need to go through this authorization process once per ONE session - that is, you will not need to login into TradeKing again unless you close down and them restart ONE..