In the latest offering aimed at retiring baby boomers, Fidelity Investments is launching a special account to help older Americans manage their money in retirement.

The new service announced last week will give consumers access to financial advisers, who can help them decide how to invest their assets, and a cash management account to help them track spending to avoid outliving their savings.

Baby boomers, the largest generation in history, are approaching retirement and need to make important decisions about spending their pensions and other savings after they stop working.

While earlier generations relied on Social Security and pensions to fund their retirement, baby boomers will have Social Security and their own savings from 401(k) accounts and other investments, experts say.

Robert L. Reynolds, vice chairman and chief operating officer of Fidelity Investments, called managing retirement assets “the largest do-it-yourself project in the history of this country” and said the Boston-based company wants to play a major role in it.

Fidelity joins a number of banks as well as brokerage and insurance companies have begun offering products and services to attract baby boomer retirement money. They range from low-cost financial planning services to products such as annuities, which are designed to create a steady stream of income.

Fidelity already has been testing out its new program, the Fidelity Retirement Income Advantage, which will be launched formally in the fall.

Consumers will be able to develop a retirement plan online or by phone or in person with a Fidelity financial adviser. After setting up an “income management account,” they will be able to keep track of their assets – including investments that aren’t with Fidelity – and track spending to ensure withdrawals are in line with their plans.

For consumers who ask, the service will provide e-mail or phone reminders when accounts should be rebalanced or quarterly taxes paid.

The service will be free to participants with $100,000 or more in assets invested in Fidelity products, she said. There will be a fee for those with lower assets, but it has not yet been set, she added.

Stephen Brobeck, executive director of the Consumer Federation of America, an advocacy group based in Washington, D.C., said that some of the new services “can be extremely helpful to consumers who are baffled by the complexity of retirement planning and execution.”

On the other hand, he said, consumers must be careful to look at the overall costs, including financial incentives that advisers have to sell certain kinds of securities or services.

Among other services already on offer is MetLife’s Income Meter, an online calculator at myretirement.metlife.com that lets consumers determine the monthly income their savings will provide in retirement. Massachusetts Mutual Life Insurance Co., meanwhile, has formed a new retirement unit to help consumers select annuities and other insurance products to fund their retirement years.

Brokerage Merrill Lynch & Co., which has been a leader in the creation of cash management accounts, is pilot testing a “retirement paycheck service” that will be launched nationwide early next year, said Jim McCarthy, a first vice president with the Merrill Lynch retirement group.

“After the long period of accumulation, the drawing down phase is going to be a growing need” that the financial services industry needs to address, he said.

He said the Merrill Lynch service will include tools for setting goals, managing investments and monitoring spending.