In a multi-page look at mobile banking (here), BankRate.com reporter Laura Bruce quotes Citibank's Rob Julavits as saying the bank will be:

…testing (mobile banking) in March and allowing customers to enroll in April, with a broad launch expected before midyear

That's a few months later than originally expected. The bank sent Citi Mobile disclosures to checking account customers in January indicating the service would be live in February (see article here). Citibank already provides mobile access to its credit cards in Japan (link here).