Yes, earning some juicy rewards for swiping American Express for your condo downpayment is nice, but if you cannot afford one, you'd better stay away from the practice -- Amex does not magically enable you to the condo.

Coming up with the money for a down payment on a new condominium may soon be as easy as charging it: American Express Co. is expected to announce today that it will allow some customers to use its cards to make condominium down payments.

For now, the service appears to be limited to a select few: luxury-condo buyers in Manhattan. American Express is rolling out the program with New York real-estate firm Moinian Group, for one of its properties currently under construction -- the Atelier condominium in Midtown Manhattan. Both companies say they plan to expand the service to other properties and partners.

For condo buyers, the deal will allow them to earn reward points or frequent-flier miles on big transactions, while extending the amount of time they have to meet the down-payment requirements and eliminating the hassle of getting certified checks. Buyers will earn one point for every dollar charged.

The program expands American Express's partnerships with real-estate merchants. The firm currently works with over a dozen property-management companies in 34 states to allow their tenants to pay rent with an AmEx card.

The move comes at a time when more landlords are allowing tenants to pay their rent with plastic. About 15% of the rental apartments in the U.S. accept credit-card payments, estimates Matt Golis, chief executive of YapStone Inc.'s RentPayment, a San Francisco processing firm that works with apartment owners and managers to enable acceptance of credit cards. Most of its new customers this year are offering to pay the costs incurred by offering credit cards as a payment alternative in order to have a competitive advantage over other properties, he says.