BOSTON — Mobile banking services, a novelty just a year ago, are suddenly taking off.

At least five partnerships were announced this week aimed at making mobile banking more widely available and more useful, and though payments executives say usage is not widespread now, they expect adoption to soar in the next year.

Giving people immediate access to real-time account details, they say, is letting banks deliver a variety of new services, including fraud-fighting alerts and location-based marketing, and could even help banks justify charging fees when people overdraw their accounts.

Prakash Hariramani, the senior business leader of global product innovation at Visa Inc., said that 4 billion mobile handsets have been deployed to date, enough for more than half the world's population, and banks cannot ignore what has become one of the most common electronic items on Earth.

"This may be the world's first ubiquitous technology," Hariramani said during a session at the Bank Administration Institute's annual Retail Delivery conference in Boston this week.

Visa, of San Francisco, announced Wednesday a partnership with the mobile banking technology company ClairMail Inc., to deliver Visa's alert capabilities through the Novato, Calif., vendor's software.

Banks and credit unions that issue Visa cards and already offer ClairMail's software can now send a variety of account alerts to customers' phones, including immediate notification of transactions. When people make purchases with an enrolled Visa card, they will receive a text message confirming the sale, often before the clerk them hands a paper receipt, Hariramani said. This can be a boon to consumers wary of fraud and to the institutions that serve them.

The alert service can also interact with phones' global positioning systems, notifying banks of users' exact locations and letting companies deliver marketing messages aimed at luring people to nearby stores.

Visa introduced some of these alert features last year, initially for handsets that use Google Inc.'s Android operating system.

Doug Brown, the senior vice president of e-commerce channels, ATM and customer service at Bank of America Corp., said that more than 3.5 million people use the Charlotte company's mobile service, and that the growth rate has been exceptional.

After introducing the service in the second quarter of 2007, Brown said, it took 13 months to attract its first million users, nine months for the second million, and just six months for the third million.

"And this is not showing any signs of slowing down," Brown said. "If you build a convenient and easy to use platform, they will flock to it."

Jim Van Dyke, the founder and president of Javelin Strategy and Research, said that 36 million people have used mobile banking services in this country at least once in the past year, about 18% of the people with phones; by 2014, he said, he expects 99 million people to be using the services, about 45% of mobile phone users.

However, he said banks need to step up their mobile offerings. His Pleasanton, Calif., research firm reports that only 18 of the nation's 40 top banks have introduced mobile services.

"Consumer interest isn't dropping, but bank systems aren't up to the task," Van Dyke said.

That situation could shift quickly, due to another deal announced this week at the conference. Intuit Inc.'s Digital Insight unit has agreed to offer its clients a suite of mobile services from Mobile Money Ventures LLC of San Francisco, a joint venture of Citigroup Inc. and SK Telecom Co. Ltd., the largest wireless telecommunications firm in South Korea.

Digital Insight serves mainly small banks and credit unions, and Taylor Driggs, its director of consumer product strategy, said only 110 of the company's 1,700 clients offer mobile banking services at all. And at the ones that have already introduced mobile services, consumer adoption rates range from 2% to above 20%, and average about 6%.

The potential interest seems to be there among consumers, especially younger people, he said. "You have to start by offering it."

One of the most common uses of mobile banking services is checking balances; people often will see how much money is in their account while waiting in line to make a purchase.

Dribben said this behavior could help banks justify charging overdraft fees, an important source of revenue that has come under fire from consumer groups in recent months. He said that when customers have the ability to find out their exact balance at any time, it can put more onus on them to avoid overdrawing their accounts and undercuts some of the arguments of consumer advocates who say overdraft fees are applied unfairly.

Two other announcements underscored the growing demand for mobile services among credit unions. PSCU Financial Services and Co-op Financial Services, two companies that provide products and services to credit unions, each said it is offering a mobile application for Apple Inc.'s iPhone.

And one of the early players in mobile banking software, Qualcomm Inc.'s Firethorn Holdings LLC, said it would integrate account transfer services from CashEdge Inc. to create a mobile phone person-to-person payments service. Several companies, including Visa, Citi, MasterCard Inc. and U.S. Bancorp, are testing or offering mobile transfer capabilities, enabling people to send money between their main bank accounts.

Despite all this activity, some executives warn that banks could still be caught flat-footed in the mobile banking race, especially in payments.

Numerous companies have tested mobile payments services that use contactless chips within the phones to initiate transactions, but such services are still not widely available.

Jaime Punishill, an executive with Citigroup's Internet and mobile team, said his company is now testing mobile payments in Bangalore, India. He said the trial, begun in June, is the world's largest to date: it involves 3,000 people now and could expand to 5,000.

Citi has been working on mobile payments infrastructure issues for 15 years, Punishill said.

"There is a pretty good reason we don't have it yet, and is the sheer difficulty of negotiating among all the players," Punishill said. "It requires all these players to come to the party and divvy up a shrinking pie in order to meet their P&L."

He said much of the current interest in mobile technology is a result of the disruptive impact of the iPhone. Apple, of Cupertino, Calif., has managed to master micropayments at its iTunes music store, where most individual song downloads cost 99 cents, and the computer maker could play a similarly disruptive role in the mobile banking and payments ecosystem, Punishill said.

"They are arguably creative enough and sneaky enough to find a way to disintermediate us."

Brown agreed that payments could prove an area where banks are outflanked by Apple, or other innovators that are equally savvy.

"If we don't get it right somebody else will," he said.