The world’s most popular premium cable channel, HBO, is slowly entering the continuously developing market of Internet video.

A subsidiary of Time Warner, HBO has launched a new service called HBO on Broadband, which offers to its subscribers the possibility of watching and downloading movies and television shows over the Web and has a much larger library than is cable-based on-demand service.

According to HBO spokesman Jeff Cusson, the service will initially be available only to Time Warner Cable high-speed Internet customers in Green Bay and Milwaukee, Wisconsin, as a free add-on to HBO and HBO on Demand and will slowly expand its availability to other parts of the country.

The free service will allow access to about 400 hours of movies and original programming each month. It will be made available only to people already subscribing to HBO, and it will be marketed and delivered through cable operators.

The HBO on Demand service comes with some limitations. First, HBO took a different approach from other networks who have embraced browser-based streaming video and offers a software that only works on Windows PCs and installs locally on the user’s computer and downloads shows to the hard drive. Then, there is a time limitation, as the stored shows expire four weeks after being downloaded. Also, the downloaded video content cannot be transfered to portable devices.

The software also ha other features like, different accounts for each family member and adult content blocking.