MSN started DSL trials Monday in Atlanta and Seattle. The company said customers in Chicago and San Diego will begin testing the service soon. Digital Subscriber Line uses conventional telephone lines to send data at speeds of up to more than 1 megabit per second.

MSN plans to offer DSL access in 20 cities nationwide by the fall.

"At Microsoft, we're focused on providing consumers with convenient, reliable and affordable high-speed Internet access that stands the test of time," said Will Diefenback, MSN Internet Access group product manager.

"Hardware and installation costs of DSL represent a significant investment for the average consumer and we're ensuring that customers will gain the full benefit of that investment by providing the fastest, easiest high-speed offering available."

DSL got out of the gate after cable modems, but is rapidly catching up thanks to accelerated plans by regional Bell telephone operators. Microsoft Corp., which has already made investments in cable modem operators, also recently got into the DSL game by taking a $30 million stake in Rhythms NetConnections Inc.. The company will also offer the DSL subscribers a co-branded MSN portal which will debut this summer.