Internet service provider UK Online has become the first to offer super-fast broadband across the UK.
The speed of ADSL2+ will depend on distance from exchange
ADSL2+ technology promises speeds of up to 22Mbps (megabits per second), although many may not get close to these speeds.
The connection speed depends on how far someone lives from a telephone exchange and the quality of their phone line.
Other internet providers, including BT, Wanadoo and Bulldog, are currently testing ADSL2+ technology.
One other firm, Be, has already launched a service although it is limited to the London area.
UK Online said its service would be available to around 4.4m homes in urban areas across the UK and the coverage would be extended over the next 12 months.
"While some customers will get 22Mbps or even more, up to 24Mbps, the quality of their phone line and distance from the exchange will dictate their maximum speed," said general manager Chris Stening.
Customers will get a free estimate of the speed they are likely to get before they sign up for the service.
The true speed of ADSL2+ has become a matter of controversy with researchers saying that many people will not get anywhere near 24Mbps.
For many, including UK Online, the service is offered via local loop unbundling
This is a process whereby other operators put equipment in BT's exchanges
Local loop unbundling is offered by several companies, including EasyNet and Bulldog
ADSL2+ is highly dependent on line quality and distance from telephone exchange
Some experts say many households will only get speeds of 8Mbps
Broadband market analysts Point Topic warned earlier this month that only 5% of the population would receive as much as 18Mbps.
To achieve the full 24Mbps, people would have to live within 300 metres of their telephone exchange, the research found.
Internet providers launching super-fast broadband packages will have to be careful not to over-sell the potential of ADSL2+, experts agree.
However UK Online remains confident that for many of their customers it will be worth upgrading from their existing 8Mbps service.
"If they live two kilometres or closer they should be able to get higher speeds than 8Mbps," said a company spokeswoman.
The service will be available for broadband junkies for £29.99 a month. On top of this, customers have to pay a one-off £25 connection charge and buy an obligatory ADSL2+ wireless router for £79.99.