Intuit has just released a handy, free iPhone app to accompany its free online financial service, Quicken Online.
Unlike the software version of Quicken, a feature-laden financial management app, Quicken Online and its Quicken Online Mobile companion app (get it here--iTunes store link) are really only designed to help you get a view into your cash flow. The main screen of Quicken Online Mobile shows you how much cash you have access to before your next payday, and it shows how you're doing against any monthly budget numbers you have set up.
You can also add new cash transactions from the app; credit card transactions get picked up automatically when the service connects to your financial institutions for updates.
Glitzy features include a cash position graph that shows up when you rotate the phone to the landscape orientation, and a location-aware ATM finder.
One big advantage of Quicken Online Mobile over competitor Mint (mobile app review) is that Quicken lets you set up a PIN password screen in front of the app, if you wish; Mint relies on you setting up a password on the iPhone itself, which would be fine--unless you like to run your iPhone without a password. (Mint does let you disable access to your iPhone app via your account page on the Mint Web site, though.)
This is a good app for keeping tabs on your cash. So's Mint, security issue aside. If you use either Quicken Online or Mint on the Web and have an iPhone, do be sure to check out their mobile apps.