Mint is the iOS mobile companion to Mint.com, the popular financial services site that helps you track all of your accounts and budgets.
You have to set up an account with Mint.com to use the app (which involves giving Mint.com access to your bank, credit card, and investment accounts), then you can monitor your accounts, budget, and cash flow from the site or the app. The passcode-protected app presents your finances in summary form, with the capability to drill down to the item level of a purchase. Follow the trail to the end to edit an item's transaction details or jot down notes or tags. You can't do everything from the app (for example, you need to go to the site to transfer money between accounts), but the latest version adds many new mobile features, including the ability to enter cash and pending transactions. The biggest change for Mint 2.0 is impressive iPad support, with interactive charts and graphs.
The Mint app has gotten much better since its initial release, with 2.0 representing a major step forward--but this app is still a supplement and not a replacement to the full-fledged Mint.com site.