You can download it from HERE to iTunes if you are on a desktop or to your iPhone's AppStore if you are on mobile safari.

You probably need to sign the real time quote agreements
1) Login at tdameritrade.com, using your TD AMERITRADE username and password
2) Click on Home -> My Profile -> General
3) Look for the section Exchange agreements
4) You need to sign all agreements, following instructions.

(Professional access differs and subscription fees may apply. For details, see our Professional Rates & Fees.)

iStockManager works with EDGE, 3G and WiFi.
Though the loading is faster with WiFi and 3G, EDGE works great too.

iStockManager works with ALL iPhones and iPods Touch.
The only requirement is to have installed firmware 2.0.0 or greater.
If you see the AppStore icon on your device, you are ready!

All account types are supported. NOTE: Accounts using the TD AMERITRADE in the Institutional platform accounts are NOT supported

Go to istockmanager.com/opentdameritradeaccount and follow steps.

They have a $0 minimum account balance and no maintenance fee.
You also can get real time quotes.

(Professional access differs and subscription fees may apply. For details, see our Professional Rates & Fees.)

iStockManager is now an exclusive product of TD Ameritrade. Our clients will continue to benefit from these innovative apps making TD Ameritrade Mobile one of the most powerful tools in your pocket and at your fingertips.

If you choose to store your password on your device, it will be stored encrypted in the "keychain". The keychain is a special module of the iPhone Operating System which stores the passwords of all applications (like mail app).
If a person gets your iPhone and your password was stored, he won't be able to see it and will need to re-enter it to trade, or cancel an order. He will be able to see your balance.
If you lose your device and you had your password stored, you should change it immediately.

All personal information (also trading information) is transmitted through HTTPS.
The "S" stands for "SECURE" (encrypted).
It's almost impossible for a man in the middle to retrieve the info transmitted.
Think that all the banks of the world use this type of encryption, so you shouldn't worry.

To do this, you must LINK YOUR ACCOUNTS.
Select a master account and login with it at www.tdameritrade.com.
Go to HOME > MY PROFILE > LINK ACCOUNTS
Sign the Linking Accounts Agreement by entering your name.
Follow the instructions to link your secondary accounts to you master account.
Now just login with your master account in iStockManager.
You will see all your linked accounts in a scroller in the "Configure" tab, just below where you enter your login information.
To select another account (to trade, see balances and orders) just scroll it.

Due to iPhone architecture there is now "multitasking", so you have to use one app at a time.
But if you save your password, iStockManager will save your session and will load a lot faster (and there will be no need to log back in)

1) Login at tdameritrade.com
2) Click on Home -> My Profile -> Subscriptions
3) Click on "Subscribe" for "Real-Time NASDAQ Level I and II Quotes" and/or "Streaming News".

1) Check your user id and passwords are OK. Check for the correct case, remember "User" is not the same as "user".
2) Check that your account is supported. Some accounts like institutional accounts are not supported.
3) If everything else fails DELETE the app by pressing iStockManager icon for 3 seconds and click on the "X" to remove. Then reinstall the app. This has helped many users, because sometime internal files are corrupted.