Imported US shows such as Lost and Desperate Housewives will not be shown, but the broadcaster is in talks with US studios to add them at a later date.
Channel 4 currently offers a pay-per-view service that lets users watch re-runs of US programs. This new venture will make it the first UK broadcaster to air its programs simultaneously on TV and online.
The online service will feature the same ads as TV, although Channel 4 plans to sell tailored advertising spaces in the future.
The BBC had previously announced plans to simulcast programs on TV, radio, and the internet before the end of 2006. ITV is also launching a broadcast service whereby programs will be aired on all platforms including mobile phones up to 30 days after their first transmission.
