BT said the hardware would stay in place after the pilot
Residents of Muswell Hill, in London, and Whitchurch, in Cardiff, are to be the first to try next generation broadband in the UK.
Exchanges in both areas are to become pilot sites where the fibre-based broadband will be tested.
Once they are upgraded, home users should be able to go online at speeds of up to 40 megabits per second (Mbps).
Up to 15,000 home and business customers in each area will get the chance to take part in the pilot.
The operational pilots will run fibre-optic cables to the street cabinets that connect homes and businesses to telephone exchanges.
A BT spokesman said the two sites were chosen because of their mix of customers and net providers in these areas as well as the make-up of the local communications network and geography.
"These two areas are perfect for our needs for the pilots," said the spokesman.
The pilots will begin in summer 2009. Prior to the start of the large scale trials BT's Openreach will run a small trial in early 2009 involving 30 homes connected to the Foxhall exchange in Kesgrave, Suffolk.
The pilots are being run by BT Openreach which looks after the so-called "first mile" of the communication network that links homes and office buildings to BT's core network.
The BT spokesman said it was proper to describe the installation of the equipment as a pilot as it would not remove the hardware once the pilot period ended.
Because of this, said the spokesman, it was not clear which broadband firms would be recruiting people to take part in the trial or the terms and conditions that would govern it.
Further pilots in new areas will be chosen towards the end of 2009 and the commercial roll out of the service is set to begin in 2010.
In July 2008, BT said it would spend £1.5bn installing fibre-optic cables to that would bring the high-speed broadband to about 40% of the UK population.
The pilot will test the technology Openreach has chosen and those taking part will be encouraged to use demanding web-based applications, such as high-definition movies and online gaming, simultaneously to see how the new system copes.
"We have no clear idea of the applications that are out there that people might need really high speed services for," said the spokesman.
In a separate trial BT is also running fibre to thousands of new homes being built at a large scale development under construction in Ebbsfleet, Kent. The technology being installed to these homes is expected to deliver speeds of about 100Mbps.
BT is not the only service provider experimenting with super-speed connections.
Virgin Media is upgrading its cable network, which serves around 50% of homes, later this year. It is due to announce which areas will benefit first in the next few weeks.
The service will offer homes speeds up to 50Mbps.