Broadcasters Channel 4 and ITV are set to launch broadband TV channels where viewers can view live and already aired programmes. The ITV service is free, while Channel 4 is charging for its 4oD service.

ITV's service, set to launch in March, will feature 30 day 'catch-ups' of programmes, as well as live broadcasts and online exclusives. It will also have user-generated content. The ITV service is free but carries advertising for revenue.

Most content from the four ITV channels will be featured on the broadband channel and can be streamed to any computer.

ITV said it has spent £20 million on the broadband service.

"Plans for our broadband portal are ambitious and well advanced," said Jeff Henry, director of ITV consumer.

Subscription-based

Channel 4's on-demand service, on the other hand, is subscription-based. Using 4oD , viewers can watch past and present Channel 4 shows from any PC at a cost of 99p for TV shows, and £2 for films. Channel 4 is currently offering the new series of Celebrity Big Brother for free as an introductory offer.

The 4oD service requires a small download (available on Channel 4's 4oD website ), which currently works with PCs only. Using the interface viewers can browse schedules from the past 30 days, or dig into around 1,000 hours of archived material.

The 4oD service also allows viewers to pre-book downloads of forthcoming shows so they don't miss any episodes.

"On-demand is the future of television. The internet means that you're not restricted to what schedulers want you to watch; now it's up to you to create your own channels.

Some of the best shows from Channel 4's 24-year history are now available to view 24/7 - that's going to totally change the way people watch TV," a Channel 4 spokesperson said.

Industry experts reacted positively to the TV channels' announcements. Steve Weller, head of communications services at price comparison firm uSwitch.com , said the news is "fantastic news for consumers, enabling them to download programmes from all four ITV channels completely free of charge, unlike Channel 4's new online TV service.

"However, we won't see families giving up their TVs just yet to watch programmes around their PC screen. Only a small majority have their PC connected to their TV and while the two technologies are converging, it will be some time yet before we see an internet-enabled TV in every home," Weller added.