The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Citibank Australia:
Citibank AustraliaBank, anytime, anywhereWith Citibank Mobile, you can be in perfect control of your finances even while on the move! You can transfer funds, pay your bills, view your account balances and access the latest promotions.Heres what Citibank Mobile Banking offers: View your account balanced and recent transactions Transfer money between your Citibank accounts and to other Citibank accounts, including Citibank Global TransferTransfer money to another bank accountPay billsView daily FX rates.With our location based service you can:Locate the nearest restaurant offering a complementary bottle of award winning wine and four points for every dollar you spend as part of the Citibank Dining Program.Locate the nearest ATM within the Citibank network within Australia and across Asia. Locate the nearest Citigold centre within Australia and across Asia Discover a world of preferential treatment, discounts and benefits within Australia and across Asia through Citibank World Privileges.